Chapter 3
STRUCTURAL FIRE PRECAUTIONS
3.1
GENERAL
3.1.1
The purpose of this chapter is to stipulate requirements to
minimise the risk of spread of fire between adjoining buildings
by separation, prevent the untimely collapse of buildings in the
event of fire by the provision of a stable and durable form of
construction and prevent the spread of fire between specified
parts of the buildings by the division of such buildings into
compartments.
Structural fire precautions relate to the integrity and stability of building
elements during fire for a required period of time. “Structural” does not only
apply to the structural elements of buildings but other building
components, e.g. doors, shafts, walls/ceiling finishes.
The objectives of structural fire precautions are :
3.2
(a)
To prevent the spread of fire between adjoining
adequate separation;
buildings by
(b)
To prevent the untimely collapse of building, including walls and
floors of each unit in the event of a fire
(c)
To prevent spread of fire from one unit to another within the building
envelope by compartmentalising each unit with walls, floors and
doors having the requisite fire resistance rating.
PROVISION OF COMPARTMENT WALLS AND COMPARTMENT
FLOORS
3.2.1
Compartment size - floor area & cubical extent
Any building which has –
(a) Any storey the floor area of which exceeds that
specified as relevant to a building of that height in
column (2) of Table 3.2A, or
(b) A cubic capacity which exceeds that specified as
relevant in column (3) of Table 3.2A,
1
shall be divided into compartments by means of
compartment walls and compartment floors so that –
(i)
(ii)
no such compartment has any storey the floor
area of which exceeds the area specified as
relevant to the building in column (2) of the Table,
and
no such compartment has a cubic capacity
which exceeds that specified as relevant in
column (3) of the Table.
Generally, the compartment size of factory or warehouse unit would not
exceed 4000m² or a cubical extent of 15000m³ as given in Table 3.2A which
is reproduced below:
TABLE 3.2A SIZE LIMITATION OF BUILDING AND COMPARTMENT
(1)
(2)
Maximum
Floor Area
(3)
Maximum
Cubical
Extent
Compartment below ground level. No
compartment to comprise more than one storey.
2000m²
7500m³
Compartments between average ground level
and a height of 24m. No compartment to
comprise more than 3 storeys.
4000m²
15000m³
Compartments above a height of 24m from
average ground level. No compartment to
comprise more than one storey.
2000m²
7500m³
Compartments
Compartment below ground level
i)
ii)
Under Table 3.2A no compartment shall comprise more than one
storey and exceed floor area of 2000m² and a cubical extent of
7500m³. However, exceptions are allowed in the following situations:
a)
Only 1st basement having a floor area of less than 100m² can
form part of the 1st and upper storey compartment under
Cl.3.2.5(a), provided the building is sprinklered protected
including the basement.
b)
Basement floors can be interconnected for use as car parking, if
sprinkler system is provided.
Basement floor or compartment shall not be used for bulk storage of
highly inflammable liquids or substances of any explosive nature.
2
Compartments between average ground level and a height of 24m
i)
No compartment shall comprise more than 3 storeys and floor area
greater than 4000m² and cubical extent exceeding 15000m³. However,
exceptions are allowed under clauses 3.2.3, 3.2.4(c) and 3.2.8.
ii)
High bay warehouse (HBW) and mechanised car parking buildings are
treated differently from normal industrial buildings.
The requirement of restricting the compartment to max. 3 storeys
would not be applicable. Such types of buildings are usually not
occupied or have very limited people working in the premises.
Automatic sprinkler system and smoke extraction or venting system are
required to be provided for high bay warehouses and mechanised car
parking buildings which exceed 24m in building height.
Compartments above a height of 24m from averaged ground level
i)
No compartment shall comprise more than one storey and exceed the
floor area of 2000m² and cubical extent of 7500m³.
ii)
This requirement would not apply to high bay warehouses and
mechanised car parking buildings. Prior consent is to be obtained from
SCD (FSSD) before submission of building plan.
General :
In computing the extent of a compartment, protected shafts e.g. lift,
staircases etc and separately compartmented lavatory/locker room may be
disregarded. See cl.1.2.16 under Definition in Vol. 1 of the handbook for
further illustration.
Clause 3.2.2 only applies to PG VI Factory, not PG VIII Storage.
3.2.2
Cubical extent for compartment exceeding 4m in height
In computing the cubical extent of compartments in shops,
similar premises and in single storey factory buildings, a height
of 4m may be used where the actual height exceeds that
figure, provided that this rule for measurement shall not be
applied when a compartment comprises more than one storey
or contains mezzanine, galleries or lofts.
For illustrations see Vol. 1 of Handbook on Definition on clause 1.2.16.
3
3.2.3
Relevant Authority may consent to greater size
Where however, the Relevant Authority is satisfied that
additional floor area and cubical extent are necessary for any
such building or compartment or part thereof, as aforesad, he
may consent to such additional floor area and cubical extent,
provided:
(a)
Such building or compartment thereof is fitted throughout
with an automatic sprinkler system which complies with
the requirements in Chapter 6,
(b)
There is proper accessibility of site to fire fighting
appliances, in compliance with the requirements in
Chapter 4,
(c)
All other measures have been or will be taken and
maintained for lessening so far as is reasonably
practicable, any danger from fire.
Such consent shall continue in force only while such building or
compartment is used for the purposes in respect of which
consent was given.
(No illustration)
Besides complying with sub-clause (a) & (b) above, the building or
compartment shall not undergo change of use, change of storage materials
and change of manufacturing processes. For example, a warehouse that
was approved for storage of non-combustible materials (valves, steel bars &
pipes) was subsequently used for storage of combustible materials (paper
boxes) would require separate building plan submission and approval from
SCDF (FSSD).
Similarly, a factory which was approved for the manufacturing of noncombustible products (precast beams, floors etc) would require separate
building plan submission and approval from SCDF (FSSD) if there is a change
of manufacturing process involving combustible materials.
In practice, where sprinkler system is provided, it would be taken that
cubical compartment and floor area control under Table 3.2A has been
relaxed, except max. 3 storey per compartment, unless further relaxation is
allowed by SCDF (FSSD) because of smoke control system being provided.
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3.2.4
Compartmentation by height
(a)
In any compartment except those mentioned under sub-clause
3.2.4(d), up to a habitable height of 24m, no compartment shall
comprise more than three storeys.
Diagram 3.2.4(a)
Where 3 storeys or levels form one compartment, the total floor area shall not
exceed 4000m² and the total cubical extent shall not exceed 15000m³.
(b)
In any building which exceeds 24m in habitable height, no
compartment shall comprise more than one storey for
compartments at storey level exceeding 24m above average
ground level.
(No illustration)
In any industrial building which exceeds 24m in habitable height, no compartment
shall comprise more than one storey per compartment from storey level exceeding
24m above average ground level. There is a need to keep the fire compartment
size small within 2000m² or 7500m³ above that habitable height as it would
otherwise pose difficulties to fire fighting and control of fire spread should there be
a fire occurrence in one of those high-rise units.
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(c)
The relevant Authority may consent to the relaxation of the
requirements under Cl.3.2.4(a) and (b) for Atrium spaces
provided the design of such spaces complies with the conditions
stipulated for “Atrium” spaces.
Diagram 3.2.4(c)
Atrium design allows multiple floors to be connected even beyond the habitable
height of 24m. The design would require the provision of engineered smoke control
system and sprinkler system. The above clause allows atrium design in buildings, but
prior approval from SCDF “FSSD” must be obtained before building plan submission
can be made. See clause 1.2.5 of Definition under Vol. 1.
3.2.5
Other cases requiring compartment walls & compartment floors
The following situations shall require compartmentation by
provision of compartment walls and/or compartment floors Separation of purpose groups
(b) Any wall and floor separating part of a building from any
other part of the same building which is used or intended to
be used mainly for a purpose falling within a different
purpose group, as identified under Table 1.2B, except the
following:
(i)
Ancillary offices located within a building
compartment of purpose group VI and VIII.
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or
(ii)
Rooms or spaces for ancillary usage located within a
building or compartment of purpose group VI and VIII as
stipulated under cl.1.2.2(B).
Diagram 3.2.5(c) - 1
Diagram 3.2.5(c) - 2
Compartment walls and floors shall be constructed of non-combustible materials to
have minimum 1 hour fire resistance rating under Table 3.3A for any of the
compartment.
3.2.5
(c) Floor over a basement
Any floor immediately over a basement storey if such storey (i)
forms part of a building or compartment of purpose
groups VI and VIII; and
(ii)
has an area exceeding 100m².
7
Diagram 3.2.5(c)(i)
Where the floor area of the basement exceeds 100sq.m it shall be a
compartment below ground level and shall not comprise more than one storey.
The basement floor shall be provided with sprinkler system under clause
6.4.1(d)(i) and dry riser under Cl. 6.2.1(b).
Diagram 3.2.5(c)(ii)
Where the floor area of basement is less than 100sq m, the floor over the
basement need not be constructed as compartment floor. Openings can be
created to connect the basement with upper storeys, subject to max.3 storey
or level in a single compartment.
All basement floors, except those under Purpose Group I & II, are required to
be provided with automatic sprinkler system under cl. 6.4.1(d)(i). Thus, where
basement floor, irrespective of its floor area, is interconnected with upper
storeys, the automatic sprinkler system required for the basement shall be
extended to cover all the upper storeys.
Clause 3.2.5(d) prohibits more than one basement floor to be connected to
form one compartment, except in the case of basement used solely for car
parking.
8
3.2.5
(d)
Basement floors
In any compartment below pavement level, no
compartment shall comprise more than one storey, except
in the case of basement used solely for car parking. No part
of a basement storey shall be used for the bulk storage of
highly inflammable liquids or substances of an explosive
nature.
Diagram 3.2.5(d) - 1
Basement 1, which has a floor area of less than 100m² can be
interconnected with 1st storey, provided it is compartmented from basement
2. Sprinkler system and rising mains are required to be provided to the
building.
Diagram 3.2.5(d) - 2
Basement 1 having a floor area of more than 100m² is required to be
compartmented from 1st storey. The above clause does not permit more than one
basement storey per compartment unless solely used for car parking. Sprinkler
system and rising main are required to be provided to basement.
9
Diagram 3.2.5(d) - 3
Owing to the special use where ramps or car lifts are needed to connect all the
floors, compartmentation is relaxed where sprinkler system and rising main are
provided.
(e)
Fire command centre
The fire command centre shall be separated from other parts of
the same building by compartment walls and floors having fire
resistance of at least 2 hours.
(No illustration)
The fire resistance rating of the walls and floors shall comply with the elements of
structure and shall have min. period of 2 hours. Any door opening into the Fire
command centre from the occupancy area shall be min. 2 hour fire rated.
3.2.5
(f)
Kitchen Separation
(i)
In an eating establishment, where a kitchen is required for
the preparation of food and / or where ‘open flame’
cooking appliances are used, the kitchen shall be
separated from other parts of the same building by
compartment wall and floor having fire resistance of at
least 1 hour;
(ii)
Openings in the compartment wall and floor shall comply
with the relevant provisions of Cl.3.9 for protection of
openings;
10
3.2.5
(f)
(iii)
Doors shall have fire resistance of half an hour and fitted
with automatic self-closing device;
(iv)
Where the flue or duct passes through the compartment
wall or floor, the flue or duct shall be encased by noncombustible construction to comply with the requirements
of Cl.3.9.5 and no damper shall be permitted to be
installed in such flue or duct; and
(v)
Separation requirement for kitchen could be exempted
under the following conditions:(a)
when all the cooking facilities in the kitchen are fitted
with approved extinguishing systems; or
Diagram 3.2.5(f)(a)
The above sub clause allows the kitchen not to be compartmented if the cooking
hood or range is installed with an automatic fire suppression system, bearing PSB
Label.
With this arrangement, there is no need to seek waiver approval from SCDF “FSSD”.
(b)
when there are at least 25% of the perimeter walls
(excluding air-well and void) of an eating establishment
open directly to the external of the building, and provided
any part of the floor space is within 9m from the nearest
opening; or
11
Diagram 3.2.5(f)(v)(b) – 1
Diagram 3.2.5(f)(v)(b) – 2
Diagram 3.2.5(f)(v)(b) – 3
12
Diagram 3.2.5(f)(v)(b) – 4
In the above situation, kitchens are not required to be compartmented.
Total ventilation openings provided along the external walls of ‘a’ and
‘b’ shall have minimum 25% of the floor area of kitchen and dining. No
part of the floor space shall be more than 9m from the external
openings. The openings referred to in walls ‘a’ and ‘b’ shall be
unobstructed vertical openings for the passage of light and air, for
example, in the case of fixed louvre window, the net ventilation opening
between over-lapping louvres is ‘x’ as given in the above sectional
drawing.
(c)
when there are at least 50% of the perimeter walls
(excluding air-well and void) of an eating
establishment open directly to the external of the
building, and provided any part of the floor space is
within 12m from the nearest opening; or
Diagram 3.2.5(f)(v)(c) – 1
13
Diagram 3.2.5(f)(v)(c) – 2
The 25% and 50% ventilation openings are required for smoke venting and relief
of accumulated heat from the area on fire. This exemption cannot be applied
in an enclosed air-conditioned environment, where the peripheral walls are
fitted with glass panel.
The 25% and 50% ventilation openings are absolute values. Extrapolation of
percentage ventilation openings based on depth of the eating establishment is
not permitted.
Diagram 3.2.5(f)(v)(c) – 3
In the above diagram the kitchens are not required to be compartmented.
Ventilation openings along the external walls ‘a’, ‘b’, ‘c’ and ‘d’ shall be
uninterrupted, having minimum 50% of the perimeter walls of the eating
establishment. The openings to the air well shall not be included in this
purpose.
14
The above requirement is more relevant to hawker centre type design.
(d)
when an eating establishment is separated from other
parts of the same building by walls and floors having fire
resistance of at least 1 hour and doors having fire
resistance of at least half an hour; and provided –
(i)
for a sprinkler protected building, there is no need
to control the floor area of the compartment; or
Diagram 3.2.5(f)(v)(d)(I) – 2
With the provision of sprinkler system, further relaxation is allowed to
permit the whole eating establishment to be enclosed with at least
1 hour fire rated walls and ½ hour fire rated door. There is no
restriction to the gross floor area of the eating establishments.
(ii)
for a non-sprinkler protected building, the floor area
of the compartment shall not exceed 150m2;
15
Diagram 3.2.5(f)((v)(d)(ii) – 1
Under sub clause d(ii) where the building is not sprinkler protected,
the area of the compartment, kitchen and dining area e.g (unit A)
shall not exceed 150m2.
LPG cylinders provided for the ‘open flame’ cooking
activities are not allowed to be located at the basement
and the installation of LPG cylinders at other areas shall
comply with provisions in the *Fire Safety (Petroleum)
Regulations.
*Now known as Fire Safety (Petroleum and Flammable Materials)
Regulations.
Notwithstanding all the above, the compartment where
‘open flame’ cooking activities is carried out shall not
comprise more than one storey
Diagram 3.2.5(f)(v)(d)(ii) – 3
16
Where ‘open flame’ cooking is used, the compartment comprising
dining and kitchen areas shall not comprise more than one storey,
notwithstanding the following :•
Building is not sprinkler protected and the compartment does not
exceed 150m2.
LPG cylinders shall not be used in any basement storey. However, piped
gas is permitted in basement storeys.
In the case of eating establishment which comprises 2 storeys, then each
storey shall be a fire compartment by itself.
3.2.5
(k)
Separation of motor vehicle workshop
A motor vehicle workshop shall be separated from any
other part of the same building by compartment walls and
floors having fire resistance of not less than 2 hours, and if
located in a basement storey of a building, shall be
separated from any other part of the same building by
compartment walls and floors having fire resistance of not
less than 4 hours.
(No illustration)
3.2.5
(l)
Separation of spray painting room
(i)
Areas in which spray painting or other allied
processes are performed or carried out, shall be
separated from other parts of the same building by
compartment walls and floors having fire resistance
of not less than 2 hours. Where spray painting booths
that have built-in vapour extraction system
complying with NFPA 33, the fire resistance
requirement is not applicable.
(ii)
Where a spray painting room or booth is protected
by an automatic sprinkler system but not complying
with NFPA 33, the fire compartment to the room or
booth can be reduced from 2 hours to 1 hour.
17
Diagram 3.2.5(I)
Spray painting booth or room shall be mechanically ventilated and enclosed in
min. 2 hour fire rated compartment to allow spraying of paint to be carried out. It
shall be constructed to prevent the escape of spray and flammable vapour
which shall be removed by the exhaust system.
The exhaust discharge point shall be not less than 5m from the inlet of any
mechanical ventilation system.
3.2.5
(m)
Coldroom
(i)
Where a coldroom has a floor area exceeding 10 sq
m, a separate outer layer of non-combustible
construction, including the door, having minimum 1hour fire resistance rating, shall be provided to
comparmentalise the coldroom enclosure from
other areas.
18
Diagram 3.2.5(m)-1
The main concern about coldrooms is the use of combustible insulation
materials for the construction of the coldroom walls, ceilings and floors. The
insulation material is usually polystyrene or polyurethane which when
subject to a fire would burn vigosously to release great amount of heat
and thick poisonous fumes.
The above diagram illustrates a cluster of coldrooms in a food processing
factory, which is sprinklered protected. The aggregate floor area of the
coldrooms is more than 20 sq m. Hence, the provision of 1-hour fire rated
outer skin of compartment walls and doors would be necessary.
(ii)
Provision of the fire resisting outer layer enclosure,
including the fire door, to the coldroom would not be
required if :
*
The coldroom has a floor area not exceeding 20 sq
m and is sprinkler protected in a building, and the
storage materials shall not include highly flammable
chemicals.
*
The coldroom is located in a kitchen compartment
(with or without ‘open flame’ cooking appliances) in
an eating establishment, provided the floor area of
the coldroom does not exceed 20 sq m, and the
kitchen is compartmentalised from other parts of the
building by compartment walls and floor having
minimum 1-hour fire resistance and door having
minimum ½-hour fire resistance, irrespective of the
relaxation allowed under cl.3.2.5(f)(v)
19
Diagram 3.2.5(m)-2
The aggregate floor area of all the coldrooms shall not exceed 20sq m if
located in a kitchen that is enclosed with 1-hour fire rated compartment walls
and ½ -hour fire door.
Diagram 3.2.5(m)-3
As the aggregate floor area of the coldrooms No. 1 and 2 is greater than 20
sq. m, each coldroom is to separately fire compartmented with one hour fire
compartment walls and fire door. The 1-hour fire rated coldroom doors, swing
or sliding type, are accepted for use, provided they are listed under the PSB
product listing scheme.
20
3.2.5
(n)
Store room
For non-sprinklered buildings, if the area of the store room
exceeds 10 m², it shall be compatmented from the other
parts of the same building by compartment walls and floors
having fire resistance of not less than 1 hour. No fire
compartmentation is required for a store room which is
housed within a sprinklered protected building.
Diagram 3.2.5(n)
Store 1 exceeding 10m² inside a factory space will need to be compartmentalised
with 1- hour fire rated enclosures.
For Store 2, which is located within a warehouse space need not to be separately
compartmented.
Store 3 which is less than 10m² still required to be provided with fire door as the store
opens into internal escape corridor.
3.2.5 (o) Areas of Special Hazard
Areas of special high risk in a building
(i)
Boiler rooms, transformer rooms, generator rooms,
storage areas of materials that are highly combustible
or flammable, and any other area of special high risk
shall be separated from other parts of the building by
compartment walls and floors having fire resistance of
not less than 2 hours. If the building is protected by an
automatic sprinkler system, the fire resistance rating of
the compartment walls and floors can be reduced to
1 hour.
21
(ii)
Rooms housing transformer containing flammable
liquid and generator rooms shall be located against
an external wall.
Diagram 3.2.5(o)
Transformer and generator rooms that contain flammable liquids should be
located against an external wall for external ventilation and explosion relief.
Transformer room
Transformers could be dry type or oil cooled type. Oil cooled type is to be
located against an external wall above ground level to allow for external
ventilation and explosion relief. Adequate precautions should be taken by the
provision of a suitable catch pit or other means to prevent the spread of fire
resulting from leakage and ignition of oil.
Generator rooms
Generator sets shall be located in clean, dry locations within fire rated
compartments. They may be placed outdoors if they are of purpose built
type, provided proper separation from unprotected openings of the building
is maintained. Generator rooms shall be located against an external wall
above ground level to allow for external ventilation and explosion relief.
Storage areas of highly combustible or flammable materials
Where possible, oil storage tanks should be installed in open air at ground
level at least 6m from adjacent buildings and in accordance with CP 40. A
max. capacity of 700 litres of diesel oil is permitted to be stored in the
generator room. The oil drum/s shall be located within a bunded area,
capable of containing 100% spillage from the drum/s.
22
Prior approval is to be obtained from SCDF (FSSD) for storage of combustible
or flammable liquids, other than in the generator room, before building plan
submission.
3.2.5
(p) Tenancy units
Fire compartmentation between individual tenancy units
within a terraced or flatted factory building shall be provided.
The entire enclosure of each of these units shall be fire
compartmented with walls and floors of minimum one-hour
fire resistance rating.
Tenancy unit
Diagram 3.2.5(p)-1
Compartment wall between units is required to be constructed of non-combustible
materials having minimum 1-hour fire resistance rating.
Diagram 3.2.5(p)-2
23
Enclosing walls and doors to internal corridor are required to be constructed of
non-combustible materials having the necessary fire resistance rating. Walls and
doors facing the external corridor are not required to be fire rated.
Diagram 3.2.5(p)-3
Compartment wall between units are required to be constructed of noncombustible materials having minimum 1-hour fire resistance rating.
3.2.6
Provision for atrium spaces
The relevant Authority may consent to modify the requirements
under Cl.3.2.1 and 3.2.4(a) and (b) of this Code for the design of
“Atrium spaces” in a building provided the following conditions are
complied with :
(a)
The minimum plan area of the Atrium void shall be not less than
93m² and no horizontal dimension between opposite edges of
the floor opening is less than 6m wide: and
(b)
Occupancy within the floor space of the Atrium meets with the
specification for low or ordinary hazard content; and
(c)
The atrium is open and unobstructed in a manner such that it
may be assumed that a fire in any part of the space will be
readily obvious to the occupants before it becomes a hazard;
and
(d)
The building is fitted throughout with an automatic sprinkler
system to comply with the requirements in Chapter 6; and
(e)
The building is fitted with an engineered smoke control system
in accordance with cl.7.6; and
24
(f)
Provision of openings and enclosures, and the planning of
means of escape shall be subject to the approval of the
Relevant Authority.
Diagram 3.2.6
The above clause allows the SCDF (FSSD) to vary the max. floor area/cubical
extent of fire compartment to allow more than 3 storeys to be interconnected
even beyond the habitable height of 24m. The critical requirements to comply with
would be the size and configuration of atrium void and provision of sprinkler system
and engineered smoke control system.
QPs shall note that all atrium designs are required to be vetted and cleared by
SCDF (FSSD) before building plan submission. The vetting refers to the concept and
the location of atrium void in the building proposal only. Calculations for the
engineered smoke control system shall be submitted separately by M&E qualified
persons.
3.2.7
Buildings of High Hazard Occupancy
(a)
The compartment of buildings of high hazard occupancy shall
not exceed one half of the sizes given in Table 3.2A and each
compartment shall comprise one storey; and
(b)
No storey of a building, the habitable height of which is more
than 24m, shall be used for the bulk storage of goods or
substances of highly combustible nature unless the building is
provided with a sprinkler system to comply with Chapter 6; and
(c)
The type of storage materials or substances shall not include the
following:
25
(i)
material that will flame up by themselves without the
presence of any fire source below the ignition
temperature of 200ºC; and
(ii)
combustible / highly flammable materials which include
those highlighted in sub-clauses (a), (b), (c) and (d) of
cl.1.2.39.
Diagram 3.2.7
3.2.8
a)
Warehouse compartments A, B & C shall not exceed 2000m² and 7500m³. Each
compartment shall comprise one storey only. The materials to be stored in the
warehouses shall exclude those listed under subclause c(i) & (ii).
b)
Buildings with habitable height not exceeding24m are allowed to be used for
bulk storage of goods or substances of highly combustible nature, except those
listed under subclause c(i) & (ii). However, if the above mentioned warehouse
buildings exceed the habitable height of 24m, the whole building must be
protected with automatic sprinkler system. Irrespective of the building height,
subclause (a) shall be complied with.
c)
Materials as listed under subclause c(i) & (ii) are not allowed to be stored in any
multi-storey building, irrespective of the habitable height.
Exemption from CL.3.2.1 on size limitation of compartment
The requirements of Cl.3.2.1 may be exempted under the following
circumstances:
(a)
Buildings used solely for the sale, storage, processing and
packaging of goods and substances of a non-combustible
nature, provided that any other parts of the buildings used
otherwise as described shall be separated by compartment
26
walls and compartment floors in compliance with the
requirements of the relevant provisions for compartment walls
and compartment floors, and
(b)
Single storey buildings of Purpose Group VI, provided that the
buildings are used solely for the sale, storage, processing &
packaging of goods & substances of a non-combustible
nature, and
(c)
Open sided car parking decks having not less than 50% of the
sides permanently open and such openings being evenly
distributed as to provide cross ventilation to all parts of the car
parking areas.
(a) & (b) – (No illustration)
For buildings or parts of building used for sale, storage, processing and packaging
of goods and substances of a non-combustible nature, there is no specific limit of
cubical extent or floor area. Each case will be considered on its merit, having
regard to fire engine accessibility provided to the site and the risk to adjacent
buildings. Prior approval from SCDF (FSSD) shall be obtained before building plan
submission. Any portion of the building that is used otherwise than as described
above should be separated from the remainder part of the building by floors, walls
and protected exit staircases having the necessary fire resistance rating as the
elements of structure of the building; and having the floor area and cubical extent
complying with Table 3.2A.
A typical standalone multi storey car park having good cross ventilation and meeting
the above sub-clause (c) of having not less than 50% of the sides permanently open
Diagram 3.2.8 – 1
27
Size limitation of the car parking floors is exempted
As the habitable height is less than 24m, automatic sprinkler system is not required.
The clear width of the airwell shall not be less than 1800mm to prevent fire from a
car from spreading vertically between split level. Provision of fire alarm system shall
be in accordance with Table 6.4A of the Fire Code.
A multi-storey car park vertically fire separated from another building
Diagram 3.2.8 – 2
Attached multi-storey car park is required to be protected by sprinkler system. The
multi-storey car park would qualify for exemption on size limitation of compartment if
sub-clause (c) is fully complied with.
Diagram 3.2.8 - 3
28
In the above situation where car parking decks form part of the multi-storey
development, having a habitable height greater than 24m, automatic sprinkler
system is required to be provided to cover the whole building. As for car parking
decks, the cubical extent and floor area could be relaxed due to cross-ventilation
under sub-clause (c).
3.3
FIRE RESISTANCE OF ELEMENTS OF STRUCTURE
3.3.1
Subject to an expressed provision to the contrary, any element of
structure shall be constructed of non-combustible materials
(excluding materials of limited combustibility) and to have fire
resistance for not less than the relevant period specified in Table 3.3A
having regard to the purpose group of the building of which it forms a
part and the dimensions specified in that Table, provided that –
(a)
Any separating wall shall have fire resistance of not less than
1-hour, and
(No illustration)
(b)
Any compartment wall or compartment floor which separates a
part of a building falling within Purpose Group II or III from any
other part of the building falling within a Purpose Group other
than Purpose Group II or III shall have fire resistance of not less
than 1-hour.
Diagram 3.3.1(b)
3.3.2
Exemption for non-load bearing external walls
Nothing in Cl.3.3.1 shall apply to :
(a)
any part of any external wall which is non-load bearing and
may, in accordance with Cl. 3.5 be an unprotected area.
29
Diagram 3.3.2
Any part of a non-load bearing external wall which constitute the unprotected
opening in pursuance to clause 3.5, is not required to have any fire resistance. In the
above diagram, the non-load bearing external wall facing the public road need
not have fire resistance if it meets Cl.3.5 on set-back requirement, measured from
the centre of the public road to the external wall.
3.3.3
Exemption for single storey buildings
In the case of a single storey building consisting of a first storey and
one or more basement storeys, nothing in Cl.3.3.1 shall apply to any
element of structure which forms part of the first storey and consists of
–
(a)
A structural frame or a beam or column, provided that any
beam or column (whether or not it forms part of a structural
frame) which is within or forms part of a wall, and any column
which gives support to a wall or gallery, shall have fire resistance
of not less than the minimum period, if any, required by this
code for that wall or gallery, or
30
Diagram 3.3.3(a)
(i)
The structural frame or beams and columns of a single storey building need
not have fire resistance under Table 3.3A, unless otherwise specified by the
Relevant Authority. The qualified persons shall, before making building plan
submission, consult SCDF (FSSD) as to the need for protection of beams and
columns in the following situations :
a)
Single storey factory or warehouse involving high hazard materials;
b)
Single storey factory or warehouse having an extensive footprint; and
c)
Single storey warehouse exceeding a building height of 10m.
(ii)
However, any beam or column which is within or forms part of a
compartment wall, separating wall or external wall (which require to have fire
resistance under clause 3.5) shall be required to have the same fire resistance
rating as the wall in which such beam or column forms part of.
(iii)
Any column or beam which give support to a wall or gallery, shall have the
same fire resistance as that required for the wall or gallery, e.g. column and
beam supporting the external wall or mezzanine floor which are required to
have fire resistance.
(b) An internal loadbearing wall or a loadbearing part of a wall,
unless that wall or part is, or forms, part of a compartment wall or
a separating wall, or forms part of the structure enclosing a
protected shaft or supports a gallery, or
31
Diagram 3.3.3(b)
An internal loadbearing wall or a loadbearing part of a wall is not required to have
fire resistance under Table 3.3A, provided the wall is not –
i)
forming part of or a compartment or separating wall
ii)
forming part of the structure enclosing a protected shaft e.g. exit staircase; or
iii)
supporting a gallery
(c)
Part of an external wall which does not support a gallery and
which may, in accordance with Cl.3.5 be an unprotected area.
Diagram 3.3.3(c)
External wall which does not support a gallery and has adequate setback from the boundary in
accordance with Cl.3.5 to be an unprotected area need not have fire resistance under Table
3.3A.
3.3.4
Interpretation and application of this regulation
The interpretation and application of Cl.3.3 shall be as follows:
(a)
Subject to the provisions of sub-cl.(b) and any other expressed
provision to the contrary, any reference to a building of which
an element of structure forms a part means the building or (if
the building is divided into compartments) any compartment of
the building of which the element of structure forms a part, and
32
Diagram 3.3.4(a)
Any reference to a building, which is divided into compartments, of which an element of
structure forms a part, means that compartment of the building (Building A).
Any reference to a building of which an element of structure forms a part means the building
(Building B). It is important to note that any element carrying another element of structure must
have at least the same fire resistance as the element it is supporting.
(b)
Any reference to height means the height of a building, but if
any part of the building is completely separated throughout its
height both above and below ground from all other parts by a
compartment wall or compartment walls in the same
continuous vertical plane, any reference to height in relation to
that part means the height solely of that part, and
Diagram 3.3.4(b)
33
The continuous vertical compartment wall divides the building into 2 parts. For
building A, any reference to height means the building height (A). For building B,
any reference to height means the building height (B). The above clause is
intended to provide relaxation for the lower building
(c)
If any element of structure forms part of more than one building
or compartment and the requirements of fire resistance
specified in Table 3.3A in respect of one building or
compartment differ from those specified in respect of any other
building or compartment of which the elements forms a part,
such element shall be so constructed as to comply with the
greater or greatest of the requirements specified.
Diagram 3.3.4(c) – 1
The warehouse as podium and factory sited on top helps to explain the fire
resistance of the lower and higher structure under Table 3.3A, bearing in mind that
the lower structures in relation to the fire resistance rating must be able to sustain the
upper higher structures of the building sited on top.
For instance, a podium of 2 storey office development (cubical extent >14,000m³)
requires a minimum 1½ hour fire resistance rating for elements of structure and a 5
storey flatted factory (cubical extent >5,500m³) sited on top of the podium requires a
minimum 2 hour fire resistance rating for elements of structure. In such scenario, the
lower structures for the 2 storey office elements of structure should be that of
minimum 2 hour fire resistance rating instead of 1½ hour fire resistance rating. The
rationale is that the lower structures must be able to sustain the structural loads of the
upper building.
34
Diagram 3.3.4(c) – 2
Diagram 3.3.4(c)-3
3.3.4
(d) If any element of structure is required to be of
non-combustible construction, the measure of fire resistance
rating shall be determined by the part which is constructed
wholly of non-combustible materials. (With the exception of
fire protecting suspended ceilings, surface materials for walls
and ceilings and floor finishes may be combustible, if they are
not relied on to contribute to the fire resistance of the wall or
floor).
(No illustration)
35
3.3.6
Suspended ceiling
In determining the fire resistance of floors, no account shall be taken of
any fire resistance attributable to any suspended ceiling unless the
ceiling is constructed specifically as a fire protecting suspended ceiling
and the construction complies with the requirements under Table 3.3B
for Limitations on Fire Protecting Suspended Ceilings.
Diagram 3.3.6
The ceiling shown in diagram 3.3.6 above, shall be constructed specifically as a fire
protecting membrane and comply with Table 3.3B on limitation of fire protecting
suspended ceiling. As the ceiling is intended as a protecting membrane, the
concealed ceiling space shall not be used for recessed lighting and other service,
such as air-con ducts, cables, pipes etc, even if these services are housed in fire
rated enclosures.
Where the space above a suspended ceiling (non-fire rated) is protected by an
automatic sprinkler system it shall be exempted from the requirements for noncombustibility and surface spread of flame classification as specified in the above
Table, provided the ceiling is not situated over an exit passageway, protected lobby
or other required protected means of escape, and that the ceiling space is not used
as an air-plenum.
The implications of clause 3.3.6 are that the normal type of suspended ceiling
consisting of separate tiles cannot be counted as contributing to the fire resistance of
the floor in buildings over 15m high where the period required is one hour; or in
buildings of any height where the period required is more than one hour. In these
circumstances only jointless ceilings can be considered as contributing.
The above diagram showing protective ceiling being added to the underside of a
timber floor, shall apply only to buildings under conservation where retention of the
timber floor is required, and in buildings under Purpose Groups I & II for the
construction of attic.
36
3.3.7
Fire rated board
Fire rated boards are permitted to be used for protection to
structural steel beams and columns in building not exceeding
the habitable height of 24m; and to beams only, except loadbearing transfer beams, in building exceeding the habitable
height of 24m; if the following conditions are satisfactorily
fulfilled:
Diagram 3.3.7
(i)
Material shall be non-combustible (BS476 Pt 4 or Pt 11); and
(ii)
It shall have fire resistance for not less than the relevant
period specified in Table 3.3A having regard to the purpose
group of the building of which it forms a part and the
dimensions specified in that Table; and
(iii) It shall meet the criteria, in terms of water absorption and
bending strength performance, when subject to test of
BS1230 Pt 1 (for gypsum plaster board) or ISO 1896 (for
calcium silicate or cement board); and
(iv) The fire rated boards shall be constructed to be in contact
with the steel column. If it is unavoidable, the void space
between the fire rated board and the steel column shall be
adequately filled to a height of 1.2m, measured from
finished floor level, with fire protective material such as
concrete, gypsum or grout to prevent any possible denting
of the boards; and
37
(v) For purpose group VI building, the fire rated boards for the
protection of columns shall be protected against
mechanical damage to a minimum height of 1.2m,
measured from finished floor level, by heavy duty metal
guard to prevent damage of the board by moving forklift,
etc. For such cases, the requirement of filling up the void
space may be dispensed with; and
(vi) There shall be no services running in the space between the
steel structure and fire rated boards, unless these services
are encased in concrete or run in steel conduits.
(No illustration)
Running of services in the space between the steel structure and fire
rated boards should be discouraged, unless it is unavoidable.
Services shall be limited to cables only and shall not include duct, gas
pipes, fuel oil pipes, etc.
3.4
TESTS OF FIRE RESISTANCE
3.4.1
Fire resistance
Performance for the fire resistance of elements of structure, doors
and other forms of construction shall be determined by reference
to the methods specified in BS 476:Part 20 to 23, which specify tests
for stability, integrity and insulation.
Specific requirements for each element in terms of the three
performance criteria of stability, integrity and insulation are given in
Table 3.4A,
(No illustration)
In conjunction with Part 20, methods of test are provided for – Beams, columns,
floors, flat roofs and walls(Part 21); Partitions, doorsets and vertical shutter
assemblies, ceiling membranes and glazed elements(Part 22); and Suspended
ceilings protecting steel beams and intumescent seals for use in conjunction
with single acting latched timber fire-resisting door assemblies(Part 23).
Part 20 specifies standard heating conditions based on a temperature/time
curve (Diagram 3.4.1) which furnaces are required to follow; the temperature at
defined locations close to the exposed face of the specimen under test rising to
821°C after 30 minutes and 1133°C after four hours.
38
Diagram 3.4.1
Standard temperature/time curve (BS 476: Part 20 )
The specimen to be tested should be either full size or, where the element exceeds
the size that can be accommodated by the furnace, it must have the following
minimum dimensions.
Non-separating
elements:
Vertical 3m high
Horizontal 4m span
Separating elements:
Vertical 3m high X 3m wide
Horizontal 4m high X 3m wide
Specimens are normally heated to simulate their exposure in a fire, eg walls from
one side, floors from beneath and columns from all sides.
Elements of building construction are required to satisfy various criteria according
to their designed function in the event of fire. These are:
“Stability” or “Loadbearing
capacity”
-
the ability of a loadbearing element to
support its test load without excessive
deflection;
“Integrity”
-
the ability of a separating element to resist
collapse, the formation of holes, gaps or
fissures through which flames and/or hot
gases could pass, and the occurrence of
sustained flaming on the unexposed face
(the side of the specimen remote from the
furnace)
39
“Insulation”
-
the ability of a separating element to resist
an excessive rise in temperature on its
unexposed face.
The criterion of “stability” or “loadbearing capacity” is applied only to loadbearing
elements. For floors, flat roofs and beams, allowable vertical deflection is limited to
1/20 clear span.
Loss of “integrity” in the context of the formation of holes, gaps or fissures is judged
by ignition of a cotton fibre pad. Where this test is not suitable, failure is deemed to
have occurred if either a 25mm diameter gauge can penetrate into the furnace
through a gap at any point, or a 6mm diameter gauge can penetrate into the
furnace through an opening and can be moved for a distance of at least 150mm.
Loss of “insulation” occurs when the temperature on the unexposed face (the side
of the specimen remote from the furnace) increases by more than 140°C (mean)
or by more than 180°C at any point. Loss of “integrity” also constitutes loss of
“insulation”.
Columns and beams have to satisfy only the criterion of “loadbearing capacity”;
glazed elements are normally required to satisfy only “integrity”; and floors and
walls have to satisfy all three criteria. It is pertinent to note that under Table 3.4A,
doors are only required to satisfy “integrity”, leaving aside “insulation” as it is
assumed unlikely that combustible materials would be stored against them.
However, doors to protected lobbies, exit staircases and exit passageways should
be provided with insulation against transmission of heat by radiation from the fire
floor into the protected enclosures which occupants use for evacuation.
It is important to note that fire rated glass door shall not be used in protected
lobbies, exit staircases and exit passageways.
3.4.2
“Deem to satisfy” provisions
An element of structure, door or other part of a building shall be
deemed to have the requisite fire resistance if –
(a)
It is constructed to the same specification as that of a
specimen exposed to test by fire in accordance with the
method and procedure under BS 476: Part 20 to 23, and
satisfied the requirements of that test for the three
performance criteria of stability, integrity and insulation for not
less than the specified period, or
(b)
In the case of a wall, beam, column, stanchion or floor to
which Appendix A to Cl.3.4 relates, it is constructed in
accordance with one of the specification set out in that
Appendix and the notional period of fire resistance given in
that Appendix as being appropriate to that type of
construction and other relevant factors is not less than the
specified period.
40
(No illustration)
Sub-clause 3.4.2(b) provides the alternative to complying with the
specification of tested prototype under BS476 Part 20 to 23. Specification
set out in Appendix A to Cl.3.4 could be used and there is no need to
obtain separate testing. However, on completion of the building works, the
qualified person concerned is to forward to SCDF “FSSD” his/her certificate
of supervision that the relevant specification listed in Appendix A to Cl. 3.4
had been complied with on site when applying for TFP or FSC.
3.4.3 Timber floors
The use of timber floors shall not be allowed.
3.5
3.5.1
EXTERNAL WALL
Requirements of External Walls shall be as follows:
(a)
Any external walls of a building or a separated part of a
building which constitutes or is situated within a distance of 1m
from any point on the relevant boundary, or is a wall of a
building or a separated part of a building which exceeds 15m
in height shall(i)
be constructed wholly of non-combustible materials apart
from any external cladding which complies with Cl.3.5.4 or
any internal lining which complies with Cl.3.13.4, and
(ii)
be so constructed as to attain the fire resistance required
by this chapter, and
Diagram 3.5.1 – (1)
41
Diagram 3.5.1- (2)
*
External wall of a building which exceeds 15m in building height or is within 1m of
the relevant boundary shall be constructed wholly of non-combustible materials,
apart from any external combustible cladding under Cl.3.5.4 or internal
combustible lining under Cl.3.13.4.
*
The external wall shall be imperforate, free of any unprotected area and have
the necessary fire resistance rating, both inside and outside. The required fire
resistance shall be achieved by the non-combustible part alone.
*
The external wall shall have the necessary fire resistance rating as follows:
the elements of structure of the building or compartment in which the wall is
located at least 1m away from in accordance with Table 3.3A, Part 1.
*
3.5.1
The whole or part of an external wall need not have fire resistance rating and can
be treated as unprotected area (such as windows etc) if it is adequately
separated from the relevant boundary in accordance with Table 2 to Cl.3.5 of the
Fire Code. Walls which are more than 1m from a boundary need to resist the
effect of fire from the inside only.
(b)
Any beam or column forming part of an external wall and any
structure carrying an external wall which is required to be
constructed of non-combustible material, shall comply with
the provisions of sub-cl. (a)
(No illustration)
Any beam or column forming part of an external wall and any structure carrying
an external wall shall be constructed of non-combustible materials and have the
necessary fire resistance rating of elements of structure, apart from any external
cladding which complies with Cl.3.5.4 or any internal lining which complies with
Cl.3.13.4. The required fire resistance shall be achieved by the non-combustible
part alone.
42
3.5.2
Exceptions
The requirements of Cl.3.5.1(a)(i) for non-combustibility of external
walls shall not apply to the external wall of a building or separated
part of a building(a)
If that wall is :
(i)
situated 1m or more from the relevant boundary; and
(ii)
not exceeding 15m in height; and
(iii) separated as described in Cl.3.3.4(b); or
Diagram 3.5.2(a)
Part of a factory or warehouse building (not exceeding 15m – building A in
diagram 3.5.2(a) - 1), separated from the other parts by vertical compartment
wall. Exemption would also apply to the separated part of building A in diagram
3.5.2(a) - 1 which shall not exceed 15m in height and be situated 1m or more from
the relevant boundary.
(b)
if that wall is situated 1 m or more from the relevant boundary:
(ii)
of single storey construction and not exceeding 15 m in
height and floor area not exceeding –
purpose group VI - 2000 m2 ;
purpose group VIII – 500m2
43
Or
(iii)
other than single storey buildings, but not exceeding 7.5
m in height and floor area not exceeding purpose group VI - 250 m2 .
3.5.3
Unprotected areas in any side of a building
Except where otherwise provided, unprotected areas in any side of
a building shall comply with the following:
(a)
Any relevant requirements relating to the permitted limits of
unprotected areas specified in Appendix B unless the building is so
situated that such side may be in accordance with Appendix B
consists entirely of any unprotected area, and
(No illustration)
Unprotected areas in relation to a side or external wall of a building means:
(i)
a window, door or other opening, and
(ii)
any part of the external wall which has less than the relevant fire resistance
required in cl.3.5, and
(iii)
any part of the external wall which has combustible material more than
1mm thick attached or applied to its external face whether for cladding or
any other purpose
The extent of unprotected areas in the external wall in relation to the setback
from relevant boundary or lot boundary shall be in accordance with Appendix B
to Cl.3.5. The further the building is setback from the relevant boundary, the
greater the amount of unprotected areas would be permitted.
An example on calculations of unprotected openings/setback from relevant
boundary is given in page 56. The intensity of the heat produced by a fire within a
building which can reach the relevant boundary will depend upon the extent of
the “unprotected areas” in the external walls and the distance between these
walls and the relevant boundary. The heat flux at the relevant boundary shall be
less than that normally required for pilot ignition of combustible material after a
period of exposure.
Thus, there is need to control the extent of “unprotected area” which can be
permitted in relation to the distance from the relevant boundary.
In situations where the extent of unprotected areas in external walls do not
comply to Appendix B, the qualified person has 4 alternatives. These are:
(a) reduce the total unprotected area; or
44
(b) increase the distance from the relevant boundary; or
(c) introduce compartmentation within the building to break up the size of
enclosing rectangle or
(d) introduce automatic sprinkler system so that the unprotected areas can be
doubled or the distance from the relevant boundary can be reduced by half.
(b) The extent of unprotected openings in an external wall of a building
or compartment in relation to its distance from the lot boundary
may be double that which is specified in Appendix B when the
building or compartment is :
(i)
used solely for the sale, storage and processing involving
goods and substances of a non-combustible nature, or
(ii)
fitted throughout with an automatic sprinkler system in
compliance with the requirements in Chapter 6.
(No illustration)
Warehouse used for storage of valves, steel bars & pipes are of non-combustible
nature. Storage used for combustible materials such as paper box would require
separate building plan submission and approval from SCDF “FSSD”.
For subclause b(ii), more relaxation is granted with installation of sprinkler system
taking into consideration the expected fire size.
(c)
The distance between the external wall of a building and the
relevant boundary may be half that specified in Appendix B if the
building is fitted throughout with an automatic sprinkler system in
compliance with the requirements in Chapter 6.
(No illustration)
The above clause is to provide an alternative for buildings protected with
sprinkler system. Qualified Person/Building owner shall decide which option,
clause (b) or (c) i.e either double the unprotected openings or half the
separation distance between the building and the relevant boundary,
whichever is relevant to the building.
(d)
The extent of unprotected openings in an external wall of a
building or part of building used for carparking in relation to its
distance from the lot boundary or relevant boundary may be
based on the floor having the largest extent of unprotected
openings for the purpose of complying with Table 1 of Appendix B.
45
Diagram3.5.3(d)
The above clause treats car park building differently by allowing the floor having
the largest extent of unprotected openings to be used for the purpose of
complying with Table 1 of Appendix B. This clause grants special relaxation in
relation to its distance from the lot boundary for the purpose of complying with
Table 1 of appendix B.
In the above diagram, the enclosing rectangle would apply to 1st storey elevation
facing the relevant boundary, instead of the whole building, which forms one
compartment.
3.5.4
Cladding on external walls
(a)
If such cladding is situated less than 1m from the relevant boundary,
it shall have surface complying with the requirements for Class ‘0’.
3.5.4
(b)
If such cladding is situated 1 m or more from the relevant
boundary it shall have, if the building is more than 15 m in
height, a surface complying with the requirements
specified for Class `0', except that any part of such
cladding below a height of 15 m from the ground may
consist of timber of not less than 9 mm finished thickness or
of a material having a surface which, when tested in
accordance with BS 476: Part 6 have an index of
performance (I) not exceeding 12 and a sub-index (i 1) not
exceeding 6.
46
Diagram 3.5.4(a)
If such cladding is situated 1m or more from the relevant boundary and the
building is more than 15m,
(i)
any part that is situated above 15m from the ground shall have a surface
complying with the requirements for Class’0’.
(ii)
any part that is situated below a height of 15m from the ground may
consist of timber of finished thickness greater than 9mm or of a material
having a surface which, when tested in accordance with BS 476 Pt 6 has
an index of performance (I) not exceeding 12 and a sub-index i1, not
exceeding 6. The index of performance is derived from the fire
propagation test which provides a comparative measure of the
contribution a material will make to the heat build-up and thus to fire
spread within a room or space.
(iii)
Values of index of performance (I) range in descending order of merit from
‘0’ (non-combustible material eg. metal) to ‘100’ (highly combustible
material). For example, 13mm thick fibre insulation board has an index of
performance (I) 66.4 and a sub-index I, 41, 18mm thick hardwood has the
value of 34.9 and a sub-index I, 9.5and 13mm thick plaster board has the
value of 9.9 and a sub-index I, 5.8. Low values indicate a low rate of heat
release.
(iv)
Values of index of performance (I) is obtained from : I = i1 + i2 + i3 where
sub-index i1, is derived from the first three minutes of test, i2 from the
following seven minutes, and i3 from the final ten minutes. A high index i1
indicates an initial rapid ignition and heat release.
47
3.5.5
Reference to Part I - II of Appendix B
Any reference to Appendix B shall be construed as referring to the
provisions of Part I of that Appendix together with the provisions of
Part II.
(No illustration)
APPENDIX ‘B’ TO CL.3.5
PART 1
CALCULATION OF PERMITTTED LIMITS OF UNPROTECTED AREAS
General rules applicable to this Appendix
1.
The permitted limit of unprotected areas in any side of a building or
compartment shall be calculated by reference to the requirements of
Part II or III (whichever is applicable under Cl.3.5)
2.
For the purpose of this Appendix, the expression “unprotected area” has
the meaning ascribed to it by Cl.1.2.61, but in calculating the size of
unprotected areas or the permitted limit of unprotected areas, the
following provisions shall apply (a)
Where any area of an external wall is an unprotected area, only
because it has combustible material attached to it as cladding, the
area shall be deemed to be half the area of such cladding;
48
Diagram 2(a) Pt.I Appendix B
Total unprotected area = W x H – ½ (W x h1)
(b)
No account shall be taken of the following –
(i)
an unprotected area which does not exceed 0.1m² and
which is not less than 1.5m from any other unprotected area
in the same side of the building or compartment (unless that
other falls within (iii) below);
(ii)
one or more unprotected areas having an areas (or, if more
than one, the aggregate area) not exceeding 1m² and not
less than 4m from any other unprotected area in the same
side of the building or compartment (except any such area
as is specified in (1) above);
(iii)
an unprotected area in any part of an external wall which
forms part of a protected shaft;
(iv)
an unprotected area in the side of a building not divided into
compartments, if the area is not less than 28m above any
ground adjoining that side of the building.
49
No account shall be taken of the following : (i)
Unprotected area not exceeding 0.1m² and not less than 1.5m from
other unprotected area
Diagram 2(b)(i) – Pt. I Appendix B
(ii)
Unprotected area or aggregate area not exceeding 1m² and not less
than 4m from other unprotected area
Diagram 2(b)(ii) – Pt. I Appendix B
50
(iii)
Unprotected area in external wall of protected shaft
Diagram 2(b)(iii) – Pt. I Appendix B
(iv)
Unprotected area above 28m of uncompartmented building
Diagram 2(b)(iv) – Pt. I Appendix B
51
PART II
Rules of calculation by reference to an enclosing rectangle
3.
The conditions of this Part of this Appendix shall be satisfied if a building
or compartment is so situated that no point on the relevant boundary is
either between relevant plane of reference and the side of the building
or compartment or at a distance from the relevant plane of reference
which is less than the distance specified in the tables to Part of this
Appendix, according to the purpose group of the building or
compartment, the dimensions of the enclosing rectangle and the
unprotected percentage.
4.
For the purpose of this Part of this Appendix:
“relevant boundary” means as defined in Cl.1.2.52 and for the purpose
of this calculation is either parallel to the side of the building under
consideration or at an angle of not more than 80° with that side;
“plane of reference” means any vertical plane which touches the side
or some part of the side of a building or compartment but which
(however far extended) does not pass within the structure of such
building or compartment (and for this purpose, any balcony, coping or
similar projection shall be deemed not to be part either of that side or of
the structure); and the relevant plane of reference shall in each case
be taken as that most favourable in that respect to the person erecting
the building;
“enclosing rectangle” means the smallest rectangle on the relevant
plane of reference which would(a)
enclose all the outer edge of any unprotected area of the building
or, if the building is divided into compartments, of the
compartment (other than any of an unprotected area which is at
an angle of more than 80° to the plane of reference the outer
edges being for this purpose projected on the plane of reference
by line perpendicular to such plane:
(b)
have two horizontal sides: &
(c)
have height and width falling within those listed in the tables to this
Part of this Appendix:
“unprotected percentage” means the percentage of the area of the
enclosing rectangle which is equal to the aggregate areas taken into
account in calculating the enclosing rectangle and as projected on it.
52
Determining the relevant boundaries
Diagram 4 – (1) Pt. II Appendix B
Relevant boundaries – where the side of a building is on the boundary, that is the
‘relevant boundary’. Otherwise it is the actual boundary of the land either parallel to,
or making an angle of not more than 80° with the face of the building in question.
Note that a boundary can be relevant to more than one face. Where land abuts a
road or canal the relevant boundary is taken as the centre of these. The points are
illustrated in Cl.1.2.52 in Vol. 1 of the Handbook.
53
Diagram 4 – (2) Pt. II Appendix B
Plane of reference to more than one face of a building
Lines A – A, B – B & C – C represent the plane of reference.
Plane of reference – A plane of reference has to be established for each side
of the building which faces a boundary. This is a vertical plane which touches,
but does not pass through the building (except for such projections as bay
54
windows, balconies, cornies etc), nor does it cross the boundary (known as the
“relevant boundary”). It must not make an angle of more than 80° with the side
of the building.
It will usually (but not always) be appropriate for it to be parallel to the boundary
and in many cases it will coincide with the face of the building. On to this all the
unprotected areas facing the boundary are projected at right angles, but
excluding any that are set at an angle of more than 80° to the plane. It is quite
possible for a plane of reference to take in more than one side of a building.
Enclosing rectangle
A rectangle is constructed on the plane of references so as to enclose the outer
limits of all the unprotected areas on that side of the building or compartment.
The enclosing rectangle is the smallest rectangle which would :
(a) enclose the outer edges of any unprotected areas;
(b) have two horizontal sides; and
(c) have height and width falling within those listed in Tables 1 and 2
Diagram 4 – (3) Pt.II Appendix B
Unprotected percentage
This is established by taking the aggregate area of all the unprotected areas
(see diagram above) as percentage of the area of the enclosing rectangle.
55
Example on calculations on unprotected areas
A
Example on calculations of unprotected openings/separation distance
requirements for factory.
Each storey is a compartment as shown in above diagram (compartments A
& B). It is assumed that the relevant boundary is parallel with the face of the
building. For calculating the unprotected areas, each compartment can be
taken separately, usually the one with the most unprotected areas. As both
compartments have the same unprotected openings, only one is taken for
the calculations.
1. Assume a rectangle (to enclose all relevant unprotected areas) = 5.5m x
11m
2. The rectangle formed under (1) is to be converted to enclosing rectangle.
Thus to use the nearest corresponding enclosing rectangle from Table 1, of
Fire Code 2002, enclosing rectangle = 6m x 12m = 72sq m
3. Unprotected areas = 32sq m (2 x 2 x 8 nos) – not relevant openings under
2(b) of Appendix B to Cl.3.5 Pt 1 are excluded e.g. openings less than 0.1m²
and located more than 1.5m from other unprotected opening; openings to
protected shaft
4. Unprotected percentage (unprotected areas as percentage of enclosing
rectangle)
= 32sq.m as percentage of 72sq.m
= 36% use 30% column in Table 2 in page 58
56
5. From Table 2 distance from boundary = 4m (minimum)
Footnote: Interpolation is permissible. By interpolating between 30% and 40%, it works out
to be 4.6m.
57
TABLES TO PART II OF APPENDIX ‘B’ TO C1 3.5 - continued
TABLE 2 - BUILDINGS OR COMPARTMENTS OF PURPOSE GROUPS
V (SHOPS), VI (FACTORY) AND VII (STORAGE & GENERAL) - OPEN-SIDED
CARPARKING DECKS SEE TABLE 1
Width of
enclosing
rectangle in
metres
3
6
9
12
15
18
21
24
27
30
40
50
60
80
100
120
No limit
Distance in metres from relevant boundary
for unprotected percentage not exceeding
20
30
40
50
1.5
2.0
2.5
3.0
3.0
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
Enclosing rectangle 6 m high
2.0
2.5
3.0
3.0
3.5
3.5
3.5
4.0
4.5
5.0
3.5
4.5
5.0
5.5
6.0
4.0
5.0
5.5
6.5
7.0
4.5
5.5
6.0
7.0
7.5
4.5
5.5
6.5
7.5
8.0
5.0
6.0
7.0
8.0
9.0
5.0
6.0
7.0
8.5
9.5
5.0
6.5
7.5
8.5
9.5
5.0
6.5
8.0
9.0
10.0
5.5
7.0
8.5
10.0 11.0
5.5
7.5
9.0
10.5 11.5
5.5
7.5
9.5
11.0 12.0
6.0
7.5
9.5
11.5 13.0
6.0
8.0
10.0 12.0 13.5
6.0
8.0
10.0 12.0 14.0
6.0
8.0
10.0 12.0 14.0
58
60
70
80
90
100
3.5
5.5
6.5
7.5
8.0
9.0
9.5
10.0
10.5
11.0
12.0
13.0
13.5
14.5
15.0
15.5
16.0
4.0
5.5
7.0
8.0
9.0
9.5
10.0
10.5
11.0
12.0
13.0
14.0
15.0
16.0
16.5
17.0
18.0
4.0
6.0
7.0
8.5
9.0
10.0
10.5
11.0
12.0
12.5
14.0
15.0
16.0
17.5
18.0
19.0
19.0
3.5.6
Buildings on land in common occupation
If two or more detached buildings are erected on land in common
occupation, any external wall of any building so erected which
faces an external wall of such other building, the relevant boundary
shall be a notional boundary passing between those buildings and
such boundary must be capable of being situated in such a position
as to enable the external walls of those buildings to comply with the
requirements of Cl.3.5.3.
Diagram 3.5.6
3.5.7
(a)
It is necessary to assume a notional boundary when two or more detached
buildings are erected on land in common occupation.
(b)
The notional boundary is taken to exist in space between the buildings and
is positioned so that the external walls of building A and B facing the
notional boundary comply with the separation distance requirement in
accordance with Tables of Appendix B, based on the percentage of
unprotected area and the purpose group of the compartment/floor.
(c)
Unprotected openings shall be assessed for each building separately. The
separation distance between the two buildings shall be not less than the
sum of the distance each building would require to a relevant boundary ie.
“a” is equal to or greater than the separation distance to the boundary for
building A and “b” is equal to or greater than the separation distance to
the relevant boundary for building B.
Vertical fire spread
For high and low parts of different compartments of a building
abutting each other, either one of the following requirements shall
be complied with to prevent spread of fire from the roof close to
and lower than the external of the higher part:
59
(a) The roof over the lower part of the building shall be fire rated
in accordance with the element of structure for minimum 1
hour for a distance of 5m measured horizontally from the
external wall of the higher part of the building; or
(b) The external wall of the higher part of the building overlooking
the roof below shall have the necessary fire resistance rating in
accordance with the element of structures for minimum 1 hour
for a vertical height of not less than 9m measured from the
lower part of the building.
(c)
the above requirements shall not be applicable to buildings or
lower parts of the building which are sprinkler protected, or old
shophouses which are subject to URA’s Conservation Programme
or built before 1969 referred to under cl.1.1.1 and cl.1.1.2
Diagram 3.5.7(a)
A fire occurring in the 3rd storey would spread vertically to 4th storey via the roof
and windows. To prevent the fire spread vertically, the roof of 3rd storey should be
fire rated for min. 1 hour for a distance of 5m measured horizontally from the
external wall of 4th storey abutting the roof of 3rd storey. The above requirement to
fire rate the roof of 3rd storey will not be applicable if the building or lower part of
the building is sprinklered protected.
60
Diagram 3.5.7(b) - 1
Diagram 3.5.7(b) - 2
Providing imperforate fire rated external wall is an alternative to fire rating the
roof under subclause (a).
The above 2 diagrams show the 2 ways of preventing fire spread vertically
from the lower floor to the upper floors.
However, if the buildings or lower part of the building are sprinkler protected,
the above requirements are not applicable.
61
3.6
SEPARATING WALLS
3.6.1
Requirement of separating walls
Every separating wall shall:
(a)
Form a complete vertical barrier in the same vertical plane
through the full height between the buildings it separates,
including roofs and basements and shall be imperforate
except for provisions of openings permitted under Cl.3.6.2,
and
(b)
Have the appropriate fire resistance to comply with the
requirements of Cl.3.3, and
(c)
Be constructed of non-combustible materials, together
with any beam and column which form part of the wall
and any structure which it carries.
(d)
Not include glass fire resisting walls.
Diagram 3.6.1 – 1
Separating wall is the common wall that separates one unit from another. It is
to prevent the spread of fire from unit to unit. The separating wall shall have
the appropriate fire resistance rating as the elements of structure of the
adjoining unit having the larger floor area or cubical extent as the case may
be. Separating wall shall be imperforate, constructed of non-combustible
materials and must have a fire resistance of not less than one hour. Openings
may be formed for the passage of small pipes or where permitted as a means
of escape under Cl.3.6.2. It shall not include fire resisting glass.
62
Separating wall applies to separating unit within the same warehouse
complex/building. It shall also apply within tenanted area for
factory/warehouse.
Diagram 3.6.1 - 2
With the separating wall brought above the roof, the concern of fire spread
through cracks and gaps caused by poor bonding/fire stopping at wall/roof
junction would be eliminated.
3.6.2
Openings in separating walls
A separating wall shall have no openings except for (a)
A door required to provide a means of escape in the
event of a fire, having the same fire resistance as that
required for the wall and complying with Cl. 3.9.2, or
(b)
A door provided for the purpose of public circulation and
permitted by the Relevant Authority, having the same fire
resistance as that required for the wall and complying with
Cl. 3.9.2, or
Openings for the passage of a pipe complying with the
relevant provisions of Cl. 3.9.3.
(c)
Sub-clause (b) is not applicable to Purpose Group VI & VIII.
(a)
Door opening between 2 industrial units is not acceptable, unless the
units are owned by one owner and occupied by a single company. In
such a case the door opening in the separating wall shall be used solely
for providing communication between the units and shall not be taken
as means of escape during fire emergency, unless otherwise allowed.
63
The owner is to furnish an undertaking to FSB that should one of the units
be sold, the door opening in the separating wall shall be bricked-up to
have the necessary fire resistance as the adjoining wall.
3.6.3
Separating wall - roof junction
A separating wall shall be either carried up to form a close joint
with the underside of a pitched roof of non-combustible
covering or carried up above the level of such roof covering.
The junctions between such separating wall and roof shall be
properly fire-stopped so as not to render ineffective the
resistance of such separating to the effects of the spread of fire.
Diagram 3.6.3
Separating wall is carried right up above the roof coverings to act as a barrier
to prevent fire spread over the roof level. The above clause addresses the
concern at the junction of separating walls with roofs and other elements of
structure to prevent fire from spreading through cracks and gaps at such
junctions.
3.6.4
Separating walls-external wall junction
If any external wall is carried across the end of a separating wall,
such external wall and separating wall shall be bonded together
or the junction of such walls shall be fire-stopped to comply with
the requirements of Cl.3.12
64
Diagram 3.6.4
3.6.5
Prohibition of combustible materials in separating walls
No combustible material shall be built into, carried through or
carried across the ends of or carried over the top of separating
walls in such a way as to render ineffective such separating walls to
the effects of the spread of fire.
Diagram 3.6.5 - 1
Combustible materials built into separating wall would weaken the fire resistance
integrity of the wall. Separating wall must be constructed of wholly noncombustible materials, including the beam, column or other structure carrying
the wall. Exception is allowed for internal linings under Cl.3.13. However, for
building under conservation, it would be acceptable if the original method of
construction of floor is required to be retained.
65
3.7
COMPARTMENT WALLS AND COMPARTMENT FLOORS
3.7.1
Requirements of compartment walls and compartment floors
Every compartment wall or compartment floor shall be required to (a) Form a complete barrier to fire between the compartments it
separates, and
(b) Have the appropriate fire resistance to comply with the
requirements of Cl.3.3, and
(c) Be constructed of non-combustible materials (together with
any beam or column which forms part of the wall or floor and
any structure which it carries), and
(d)
Have no fire resisting glass forming part of it unless permitted
under cl.3.15.13.
(No illustration)
Compartment walls and floors are to be totally imperforate except for the
following permitted openings :
(a)
(b)
(c)
(d)
(e)
doors
protected shafts
ventilation ducts
pipes
chutes eg. refuse, linen
Compartment walls and floors are to be constructed wholly of non-combustible
materials, including any beam or column which forms part of the wall or floor
and any structure which it carries. The walls and floors shall be constructed to
have the necessary fire resistance of min. 1 hour to comply with the requirements
of Cl.3.3. See alsoCl.3.2.5 on the provision of compartment walls and floors.
Provision of fire resisting glass in compartment wall or floor separating residential
units is not allowed under Cl. 3.15.13, provided the building is sprinkler protected.
3.7.2
Openings in compartment wall or compartment floor
A compartment wall or compartment floor shall have no openings
in it, except for (a) A door which has the same fire resistance rating as the
compartment wall and complies with the relevant
requirements of Cl. 3.4, unless permitted by other provisions of
the Code, or
66
(b) A protected shaft which complies with the requirements of Cl.
3.8, or
(c) The passage of a pipe or ventilation duct, such openings in
the compartment wall or compartment floor shall be
protected to comply with the relevant provisions of Cl. 3.9.
It is common practice to provide ½ hour fire resistance entrance door to flat or
maisonette from common space, eg lobby. The fundamental reasons are that
entrance doors are subject to normal everyday usage and that it is generally
accepted that no combustible materials would be placed behind the doors.
In other situation, the door within compartment wall shall have the same fire
resistance as the compartment wall. This is applicable to trap doors in floors.
c) – ventilation duct passing
through compartment wall
Fire damper
Fire stopping
(compressible noncombustible
material
Ventilation duct
Compartment wall
Diagram 3.7.2(c)
67
Compartment walls and floors are required to be totally imperforate except for the
abovementioned openings to permit movement of people, air, services etc in the
building.
3.7.3
(a) Junction with other structures
Where a compartment wall or compartment floor forms a
junction with any structure comprising any other
compartment wall, or any external wall, separating wall or
structure enclosing a protected shaft, such structures shall be
bonded together at the junctions or the junctions shall be
fire-stopped to comply with the requirements of Cl. 3.12.
(b) Opening in curtain walling
The opening occurring at the junction between the edge of
a structural floor and the curtain walling shall be sealed to
prevent the spread of smoke and flame from the lower floor
to the upper floor via the opening. Materials to be used for
sealing the opening shall have the requisite fire resistance
rating as the elements of structure.
See subclause 3.6.4 (Separating wall – external wall function)
Diagram 3.7.3(b)
3.7.4
Compartment wall – roof junctions
Where a compartment wall forms a junction with a roof, such
compartment wall shall be carried up to form a close joint with the
underside of the roof and shall be properly fire-stopped or shall be
carried ip above the level of the roof covering and the junction
68
between such compartment wall and roof shall be properly fire –
stopped so as not to render ineffective the resistance of such
compartment wall to the effects of the spread of fire.
Diagram 3.7.4
Compartment wall shall be brought up to the underside of the roof coverings,
including jack roof to complete the fire separation and to prevent fire spread from
compartment to compartment. See also sub-clause 3.6.3 (separating wall – roof
junction)
3.7.5
Prohibition of combustible materials
No combustible material shall be built into, carried through or carried
across the ends of any compartment wall or compartment floor or
carried over the top of any compartment wall in such a manner as to
render ineffective the resistance of such wall or floor to the effects of
the spread of fire.
See subclause3.6.5 (Prohibition of combustible material in separating wall)
3.7.6
Non-combustibility of compartment walls or floors
Every compartment wall or compartment floor shall be constructed of
non-combustible materials, unless permitted by the Relevant
Authority.
Construction of compartment walls and floors is to be entirely of non-combustible
material, except for compartment walls or floors in buildings which are required to
be retained by URA under the conservation programme. There are also certain
other exceptions :
a) floor finishes
b) wall or ceiling linings complying with Cl.3.13
c) suspended ceilings under Cl.3.3.6
69
Any structural members carrying compartment walls or floors must also comply with
the requirement of non-combustibility. Apart from the contribution made by
suspended ceilings under CL.3.3.6, the fire resistance of the structural members must
be attained without assistance from any combustible material (with the exception
of buildings designated for conservation).
3.8
PROTECTED SHAFTS
3.8.1
Purpose of protected shaft
A protected shaft shall not be used for any purpose additional to
those given as defined under Cl. 1.2.47.
All services such as, pipe/duct installation should not be located inside
protected staircase. Likewise, no washroom is allowed to be located
inside protected staircase.
(No illustration)
The purposes of providing protected shaft are to delay or prevent the spread of fire
between compartments through which staircases or other shafts pass directly and
to enable people or things or air to pass between compartments. “Protected
Shafts” include stairways, lift shafts, chutes, ducts or any other shaft enabling
movement of people, goods, air, pipes, etc.
Protecting structures shall be treated as elements of structure for the purpose of
determining the period of fire resistance rating.
3.8.2
Requirements of protected shaft
Every protected shaft shall be required to –
(a)
Form a complete barrier to fire between the different
compartments which the shaft connects, and
(b)
Have the appropriate fire resistance to comply with the
requirements of Cl. 3.3, and
(c)
Be constructed of non-combustible material (together with
any beam or column which forms part of the enclosure and
any structure which carries it).
70
Diagram 3.8.2
See Cl.1.2.48 under Definition (Volume 1)
Where the protection afforded to a compartment is penetrated to allow the movement of
people, goods or anything else between compartments by means of eg. a staircase, lift or
duct, the protection to the compartment must not be lowered or diminished. This is achieved
by enclosing the means of transportation from one compartment to another in a protected
shaft which is so constructed that any penetration of the enclosures to the shaft poses no
direct or indirect threat to the compartments connected by the shaft. Hence, the terms
“protected shaft” and “protecting structure” for the structure enclosing such a shaft. The
elements enclosing the shaft (unless formed by adjacent external walls) are compartment
walls and floors.
Figure (iii) of the above diagram illustrates a shaft which is enclosed by compartment or
separating wall, external wall and internal walls called protecting structure. The fire
resistance of the compartment or separating wall should be based on the size of the floor
area or cubical extent of the adjoining larger compartment and shall not be less than 1 hour
The fire resistance of the external wall would be determined by the separation distance
requirements under Cl.3.5. The external wall is not a protecting structure and could be fully
unprotected areas having no fire resistance. The remaining 2 walls of the shaft are protecting
structure which must be imperforate except for certain permitted openings, eg. inspection
doors which need to have fire resistance equivalent to half that of the protecting structure.
71
All protecting structure shall be constructed of non-combustible material except for surface
linings which shall comply with Cl.3.13. The fire resistance of the protecting structures shall be
that for the elements of structure of the building.
3.8.3
Openings in protected shaft
A protected shaft shall have no openings in its enclosure, except(a) In the case of any part of the enclosure which is formed by a
separating wall, any opening which complies with the
requirements of Cl.3.6 for separating walls, or
(b) In the case of any part of the enclosure which is formed by a
compartment wall or a compartment floor, any opening which
complies with the requirements of Cl.3.7 for compartment wall or
compartment floor, or
(c) In the case of any part of the enclosure which is formed by the
protecting structure –
(i)
a door which has the appropriate fire resistance to
comply with the requirements of Cl. 3.4 for test of fire
resistance, or otherwise permitted by provision of Cl.
3.8.6, or
(ii)
the passage of a pipe, excluding protecting structure to
exit staircase and exit passageway, or
(iii)
inlets to and outlets from and opening for the duct, if the
shaft contains or serves as a ventilation duct,
such openings in the protected shaft shall be protected to comply
with the relevant provisions of Cl. 3.9 for protection of openings.
72
Diagram 3.8.3 (a)
Diagram 3.8.3 (b)
Protected shaft bounded on three sides by protecting structure and fourth side by an
external wall. Permitted opening to each unit shall be protected by a door of at least
one half of the fire resistance rating of the enclosing wall, or half an hour, whichever is
the greater. The aggregate fire resistance of the 2 doors shall not be less than the fire
resistance of the protecting structure.
73
Permitted openings in protected shaft
Diagram 3.8.3(c) – 1
Diagram 3.8.3(c) - 2
74
Diagram 3.8.3(c) - 3
Fire resisting doors to comply with Cl.3.9.2 and shall have ½ hour fire resistance or half the
resistance of the enclosing walls, whichever is the greater.
1)
Any opening in compartment floor/wall would constitute a break in
compartmentation. Therefore even small service pipes, strictly speaking must be
enclosed in protected shaft.
2)
However, clause 3.9 allows pipe size not greater than those sizes provided in Table 3.9A
to be unprotected, provided the pipes are to be spaced at min. 50mm apart or half
the diameter of the larger pipe, whichever is larger. This is to avoid clustering of pipes
which would weaken the compartment floor or wall
3)
Openings in compartment floors to accommodate staircases, lifts and services form a
vertical shaft which can become a ready means of passage of fire from one storey to
another, accentuated by the flue effect created by a fire.
4)
Hence, protected shafts are needed to maintain the overall fire integrity of the
building. However, these shafts need to have door openings for movement of people,
eg. staircase, lifts and maintenance purposes in the case of shafts containing services.
All the door openings to protected shaft are considered the sources of weakness in the
integrity of the shafts and they must be protected.
5)
Door openings
Doors in protected shaft must have at least ½ hour fire resistance rating or half the fire
resistance of the protecting structure whichever is greater.
75
6)
Such a relaxation from the full standard of fire integrity is reasonable as it is expected
that combustible materials would not be placed next to the door and that a fire has to
break into the shaft and break out again at the upper level. Also if the top of the shaft
is adequately ventilated, the tendency for lateral spread is considerably reduced.
7)
The primary purpose of protecting structure is to provide the compartmentation
between floors. As such the structure shall have full fire resistance as the elements of
structure. The relaxation on fire resistance accorded to fire doors shall not be extended
to the protecting structure ie. halve the fire resistance of the elements of structure. The
main reason is that by halving the fire resistance of protecting structure, the threat of
failure and collapse of the enclosing walls would be greater in times of fire emergency
and should the walls collapse, large opening would be created in the shaft to permit
the spread of fire and smoke, which is not acceptable. As to door openings in
protected shaft, the eventual failure of the fire door is considered acceptable owing
to the limited door opening size. See illustrations (c) and (d).
8)
Ventilation ducts
Ventilation ducts are usually constructed of sheet metal, which do not have fire
resistance and therefore should a fire occur, they will quickly distort and collapse
leaving a hole in any wall through which they pass. Conversely, a fire occuring in the
duct could also cause collapse.
9)
Therefore, where the duct penetrates the protected shaft, a fire damper should be
fitted at the opening of the protecting structure. The fire damper shall be capable of
sealing the opening in the protecting structure and be installed independently of the
duct trunking. In this way, the fire damper would not be affected by collapse of duct
work and be able to maintain the fire integrity of the shaft. See illustration (a).
10)
Pipes
Where pipes are contained within a protected shaft, the problem of maintaining the
integrity of the fire compartment is made simple, irrespective whether the pipes are
made of UPVC or combustible materials. However, for gas pipes or pipes containing
combustible liquids, they shall be located in separate shafts.
11
The construction of gas pipes shaft is different from other shafts owing to the need to
provide through or external ventilation. Gas pipe shaft shall comply fully with SS CP 51.
See illustration (b).
12)
General
In order to maintain the level of integrity of protected shafts, openings in protected
shafts shall be restricted to the following :
a) Openings for pipe
b) Door openings to lift shaft, staircase
c) Openings for ventilation ducts
d) Access openings for electrical cables shaft
e) Openings for chutes, linen or refuse.
76
3.8.4
Non-combustility of protecting structures
Every protecting structure shall be constructed wholly of noncombustible materials except that floor, wall and ceiling finishes
which do not contribute to the fire resistance of such protecting
structure may not be required to comply with the requirements for
non-combustibilty.
(No illustration)
The requirement that all protecting structure shall be constructed of noncombustible materials is also spelled out under Cl.3.8.2. As to the provision of
combustible finishes to floor, wall and ceiling, it must be observed that such
provision will not be permitted inside protected shafts that are used for the passage
of people such as exit staircases, exit passageways and smoke-stop lobbies under
Cl.3.10.4 and Cl.3.13.6.
3.8.5
Ventilation of protected shaft
Ventilation of protected shaft shall comply with the following:
(a) A protected shaft used for the passage of people, such as exit
staircases, shall be ventilated to comply with the relevant
provisions of the Code.
(b) A protected shaft containing a pipe conveying gas shall be
adequately ventilated directly to the outside air or other modes
of ventilation allowed under SS CP 51.
(No illustration)
Protected shaft used for passage of people, such as exit staircases shall be
provided with adequate natural ventilation by fixed openings in the external walls.
Such openings shall have an area of not less than 10 per cent of the floor area per
floor of the staircase. Alternatively, the staircase can be mechanically ventilated
under Cl.2.3.3(f). However, for internal exit staircase serving more than 4 storeys, the
supply air shall be mechanically conveyed via a vertical duct extending through
the staircase height and discharging from outlets distributed at alternate floor.
Where the internal exit staircase exceeds 24m in height without provision for natural
ventilation, the staircase shall be pressurised in accordance with Cl.2.3.3(g).
The mechanical ventilation system to internal staircase serving more than 4 storey
and the pressurization system to internal exit staircase exceeding 24m shall be
connected to emergency power supply. In addition, a remote manual start-stop
switch shall be make available to fire fighters at the fire command centre, or at the
fire indicating board where there is no fire command centre. The start-stop switch
provides the fire fighter a quick means to shut-off the fans should it be detected
77
that smoke had been drawn into the staircase by the fresh air supply fan.
A protected shaft conveying piped flammable gas should be adequately
ventilated directly to the outside air by ventilation openings at high and low level in
the shaft or comply with the modes of ventilation allowed in CP51. All gas pipe
installations shall be vetted and approved by acceptable organisation (example:
Powergas) before any works can be carried out on site.
3.8.6
Doors in protecting structures
Any door fitted to an opening in protecting structure shall have fire
resistance for not less than half the period required by other provisions
of the Code for the protecting structure surrounding the opening.
Exception :
Any door fitted to an opening in protecting structure of a shaft
containing services such as electrical cables, pipes, ducts would not
need to have the fire resistance rating if the door is located along the
wall facing the external corridor.
Diagram 3.8.6
As the doors in the electrical and pipe shafts are opening into an external corridor
which is naturally ventilated, there is no need to fire rate the doors
Protected shaft A serves 2 compartments. Compartment A could be a common
area eg. lounge and compartment B in factory/warehouse unit.
Door A1 is opening in the direction of exit travel, whereas door A2 is the entrance
door of the factory/warehouse unit, which swings inward. The number of exit door
openings in a protected shaft containing an exit staircase shall not exceed two per
floor. This is to prevent additional openings from weakening the integrity of the
protecting structure.
The aggregate fire resistance of door A1 and A2 shall not be less than the
compartment wall or the protecting structures to the shaft. This is to ensure that the
fire resistance between compartment A and B is not reduced at the door openings.
78
Door A1 can be held in the open position provided it is fitted with electro-magnetic
or electro-mechanical device. See Cl.1.2.20 in Volume I.
All doors in shaft A & B shall have the fire resistance rating of half that of the
enclosing protecting structures to the shafts, but shall never be less than half hour.
See also Cl. 3.8.3 for further explanation.
3.8.7
Protected shaft containing exit staircase
A protected shaft which contains an exit staircase shall comply with
the following:
3.8.7
(a)
It shall not contain any pipe conveying gas or combustible
liquid.
(b)
It shall not contain any services that are not solely serving the
same exit staircase except for:
(c)
(i)
cut-off sprinkler and pipe for that staircase; and
(ii)
UPVC or cast iron rain water downpipes serving the roof
directly above the exit staircase, and not routed through
anywhere outside the staircase.
The protecting structure shall be constructed of masonry, or
drywall. If drywall construction is used, the following conditions
shall be complied with :
(i)
Drywall shall be non-combustible; and
(ii)
Drywall shall have fire resistance for not less than the
relevant period specified in Table 3.3A having regard to
the purpose group of the building of which it forms a
part and the dimension specified in that Table; and
(iii)
Drywall shall meet the criteria, in terms of impact and
deflection performance, when subject to the tests of BS
5588 Pt 5 Appendix A and BS 5234 Pt 2; and
(iv)
Drywall shall meet the criteria, in terms of water
absorption and bending strength performance, when
subject to the test of BS 1230 Pt 1 (for gypsum plaster
board) or ISO 1896 (for calcium silicate or cement
board); and
79
(v)
The building shall have at least two independent exit
staircase shafts (scissors staircases are considered as
single shaft).
Diagram 3.8.7(c)(v)-1
Building designed with single exit staircase shall have the protecting
structure constructed of masonry, which is more solid and stable
than fire rated dry walls. The main concern is that if the protecting
structure, which is constructed of dry wall is damaged, smoke and
heat would get into the staircase to affect the evacuees making
their way down. Single Exit Staircase shall have its protected
structure constructed of masonry.
Diagram 3.8.7(c)(v)-2
Where two independent staircases are provided, the protecting
structure to each of the staircase can be constructed of drywall.
80
Diagram 3.8.7(c)(v)-3
Where a building is designed with a pair of scissors staircases to
meet the provision of exit requirements, the scissors staircases shall
be considered as within a common shaft if drywall is used for the
construction of the protecting structure. The main reason is that if
one of the shaft is damaged, the other shaft is likely to be affected,
thereby causing smoke to get into both staircases. This would
render the pair of scissors staircases inaccessible. In addition, the
drywall enclosures are prone to other damages, thus affecting the
effectiveness and integrity of the protected shafts. However, for the
purpose of exit computation, the pair of scissors staircases shall
literally be taken as 2 staircases though it could only qualify as a
single shaft.
Diagram 3.8.7(c)-1
Non-combustible steel studs, insulation materials and fire rated boards shall be used
for the construction of drywall.
81
Diagram 3.8.7(c)-2
An exit staircase designated as fire fighting staircase in a building which exceeds
24m in habitable height has to be complemented by fire lift and fire fighting lobby.
Separate ventilation shafts are required to be provided for the staircase and fire
fighting lobby.
Exit staircases serving any building irrespective of the height, shall be deviod of
combustible wall, floor and ceiling finishes. Building services which are not solely
serving the exit staircase shall not be allowed to be routed through or inside the
staircase. This is to prevent any possibilities of a fire occurring inside the staircase and
the spread of fire into the staircase via the services such as electrical cables, ducts,
combustible pipes, etc. Clause 6.2.2 of the Fire Code allows vertical stack of rising
main and landing valve to be located inside the staircase as a last resort where
smoke-stop lobby and common area outside the staircase are not available. Clause
2.4.3 of SS CP 10 allows sub-alarm panels to be located in the exit staircase provided
there is no fire lift lobby or smoke-stop lobby in the building. The fire alarm cables shall
be in metal conduit or trunking. This relaxation shall not apply to buildings which are
more than 4 storeys in height where provision of smoke-stop lobby is a requirement.
The exit staircases are the means of escape in fire emergencies. All occupants must
use the staircases to evacuate safely from any storey level to the final exits at ground
level. The time taken to descend a staircase in a high-rise buildings could be more
than an hour. With the staircase fully packed with evacuating occupants during an
emergency, the staircase must be maintained safe from smoke, heat and fire
throughout the fire resistance period of the enclosing protecting structures to the
staircase. In view of the above and to prevent any mechanical damage, masonry
construction to the protecting structure is usually preferred. An exception is allowed
under Cl.3.8.9(d) for maximum 4 storey residential building where services are allowed
to be located inside the staircase enclosure.
82
3.8.8
Lift shaft
A protected shaft which contains a lift shall comply with the
following:
(a)
It shall not contain any pipe conveying gas or
combustible liquid, other than those in the mechanism
of a hydraulic lift.
(b)
The protecting structure shall be constructed of
masonry, or drywall. If drywall construction is used, the
following conditions shall be complied with :
(i)
Drywall shall be non-combustible; and
(ii)
Drywall shall have fire resistance for not less than the
relevant period specified in Table 3.3A having
regard to the purpose group of the building of
which it forms a part and the dimension specified in
that Table; and
(iii)
Drywall shall meet the criteria, in terms of impact
and deflection performance, when subject to the
tests of BS 5588 Pt 5 Appendix A and BS 5234 Pt 2;
and
(iv)
Drywall shall meet the criteria, in terms of water
absorption and bending strength performance,
when subject to the test of BS 1230 Pt 1 (for
gypsum plaster board) or ISO 1896 (for calcium
silicate or cement board); and
(v)
Drywall shall meet the criteria of Cyclic Loading
and Dynamic test as specified under Cl. 3.3 of
Building Code of Australia Specification C 1.8.
83
Diagram 3.8.8(a) & (b) - 1
Lift shaft which is not located at the edge of atrium floors or at the
external wall outside the building shall be constructed of masonry or
drywall, provided requirements under 3.8.8(b) are fully complied with.
Sub-clause (a) above specifically permits combustible liquid in the
mechanism of hydraulic lift. The liquid is concealed in vessels and forms
part of the mechanical system to permit the homing of the lift during an
emergency. The liquid has a high flash point of over 400°C.
3.8.8 (c)
Factory
Where a lift is either located at the edge of atrium
floors or at the external wall and outside the building,
the lift shall be considered as not enclosed within a
protected shaft.
Storage
Where a lift is located at the external wall and outside
the building, the lift shall be considered as not
enclosed within a protected shaft.
84
Diagram 3.8.8(c) - 1
In the above diagram the lift is unenclosed, being located within the
atrium void. There is no penetration of any compartment floor and
smoke migration caused by the ‘piston-effect’ of lift movement is no
longer a concern. Smoke from a fire in any occupancy floor will flow
from the ceiling layer into the atrium void where it will tend to rise
upwards due to its natural buoyancy. A smoke control system would
eventually extract the smoke out of the building
Diagram 3.8.8(c) - 2
85
The lift is sited outside the external wall of the building. There is no
concern of smoke and heat being transferred from floor to floor. Hence
it is not required to be enclosed in a protected shaft. This type of lift is
commonly known as ‘bubble lift’ or ‘sky lift’.
Diagram 3.8.8(c) - 3
The above diagram shows that the lift is located away from the atrium void. As
the lift punctures through the compartment floors, it must be enclosed in a
protected shaft to prevent the spread of smoke and heat from floor to floor.
(d)
(e)
(f)
The protected shaft shall be vented in accordance with SS
CP 2 Code of Practice for Installation, Operation and
Maintenance of Electric Passenger and Goods Lifts. The
vents shall be so arranged as to induce exhaust ventilation of
the shaft. Where vents could not be provided because of
the location of the lift shaft, ventilation duct protected by
drywall complying with Cl.3.8.8(b) serving as ventilation of the
shaft may be provided instead. If the duct is not to be fire
rated, fire dampers shall be provided to the duct at the wall
of the lift shaft, provided such relaxation shall not apply to
shaft containing fire lift.
Openings for the passage of lift cables into the lift motor
room located above or at the bottom of the shaft shall be as
small as practicable.
Transom panel above lift entrance shall be considered as
part of the protecting structure and shall therefore conform
to the fire resistance requirements of the protected structure.
86
Diagram 3.8.8(e)
Floor indicator panel should be surface mounted. If it is built into the transom
panel, care should be taken to ensure that the fire resistance of the panel is not
lowered. It is a common mistake to puncture the transom panel to receive the
floor indicator panel without giving consideration to the fire integrity of the panel.
Such practice contravenes the above requirement, as Cl.3.8.2 requires that the
protecting structure, including the transom panel, forms a complete barrier and
should have the appropriate fire resistance rating.
3.8.8
(g)
If it serves any basement storey and not adjoining any void
connecting to upper levels or any external spaces, there shall
be provided a lobby enclosed by walls having fire resistance
of not less than 1 hour and fire door of not less than half an
hour.
87
Diagram 3.8.8(f) - 1
Lift opening into basement and not adjoining a void that opens to the sky or
any external spaces, shall be provided within a smoke stop lobby having 1hour fire rated enclosures and ½ hour fire door.
The smoke-stop lobby acts as a buffer zone to prevent smoke from being
drawn into the lift shaft through the ‘piston-effect’ of the movement of the lift.
Diagram 3.8.8(f) - 2
Lift opening into basement storey and adjoining a void opening to the sky or
any external spaces does not require a smoke-stop lobby. Smoke occurring in
the vicinity of the lift would be drawn into the void and vented upward into
the open space. This provision would help to reduce the chance of smoke
being sucked into the lift shaft.
88
3.8.9
Protected shaft containing other services installations
A protected shaft used for the enclosure of services shall
comply with the following:
(a)
The protecting structure for protected shaft containing
kitchen exhaust ducts and mechanical ventilation
ducts serving areas specified in Cl.5.2.1(g)(i) to (iii) and
(h) which pass through one or more floor slabs shall be
of masonry or drywall. Such shaft shall be completely
compartmented from the rest of the shaft space
containing other ducts or any other services
installations. Protected shaft containing ducts serving
other areas which pass through two or more floor slabs
shall be constructed of drywall. If the protecting
structure for the protected shaft is constructed of
drywall, the following conditions shall be complied with
:
(i)
Drywall shall be non-combustible; and
(ii)
Drywall shall have fire resistance for not less than
the relevant period specified in Table 3.3A having
regard to the purpose group of the building of
which it forms a part and the dimension specified
in that Table; and
(iii)
Drywall shall meet the criteria, in terms of impact
and deflection performance, when subject to the
tests of BS 5588 Pt 5 Appendix A and BS 5234 Pt 2;
and
(iv)
Drywall shall meet the criteria, in terms of water
absorption
and
bending
strength;
and
performance, when subject to the test of BS 1230
Pt 1 (for gypsum plaster board) or ISO 1896 (for
calcium silicate or cement board).
The protecting structure for protected shaft containing kitchen exhaust duct
and mechanical ventilation ducts which pass through one or more floors and
serving areas such as:
(i)
(ii)
(iii)
exit staircases and exit passageways
Smoke-stop and fire fighting lobby
Areas of refuge within the same building
89
(iv)
(v)
Emergency generator
Engine driven fire pump
shall be constructed in masonry or dry wall. Each shaft shall be separately
compartmented from one another. Protected shaft containing ducts serving
other areas not mentioned above and which pass through two or more floors
can be constructed of fire rated materials, instead of masonry.
(i)
Diagram 3.8.9(a) – 1
Eg. kitchen exhaust duct shall be in a separate compartment from that for a
mechanical ventilation duct. Kitchen exhaust ducts serving different kitchens
shall be in separate shafts. Mechanical ventilation duct serving the area of
refuge shall be in different shaft from that serving the pump room. The main
reason for separate shafts is to prevent smoke and fire spread from shaft to
shaft.
90
(ii)
Diagram 3.8.9(a) - 2
Kitchen exhaust shaft for each kitchen is completely separated. The horizontal
run of the exhaust from kitchen 1 is protected with fire rated material.
(iii)
Diagram 3.8.9(a) - 3
If a flue, or duct containing flues or appliance ventilation duct(s), passes
through a compartment wall or compartment floor, or is built into a
compartment wall, each wall of the flue or duct should have a fire resistance
of at least half that of the wall or floor in order to prevent the by-passing of the
compartmentation.
91
3.8.9
(b)
Protected shaft used for the enclosure of electrical power
services shall be interrupted at every floor level with barriers
with fire resistance of at least half an hour. Protected shaft used
for the enclosure of telecommunications cables shall be
interrupted by barriers with fire resistance of at least half an
hour at vertical intervals not exceeding 15m. Such cavity
barriers shall comply with the relevant provision of Cl.3.11.
(i)
Diagram 3.8.9(b) – (i)
Protected shaft containing electrical cables shall be interrupted at every
floor with cavity barrier having min. ½ hour fire rating to prevent vertical
spread of fire and smoke. The main concern is that cables are a source of
fuel and ignition. The presence of fire stopping at every floor would help to
confine fire to a single storey or segment of the shaft.
(ii)
Protected shaft containing Telecom cables
Protected shaft used for the enclosure of telecommunications cables shall
be interrupted by barriers with fire resistance of at least half an hour at
vertical intervals not exceeding 15 m. Such cavity barriers shall comply with
the relevant provisions of Cl. 3.11.
92
Diagram 3.8.9(b) – (ii)
Protected shaft containing telecommunications cables including cable TV
lines is provided with cavity barrier at vertical intervals not exceeding 15m or
3 storey whichever is the shorter. The cables are mainly of low voltage and
hence of a lower risk when compared to electrical cables.
3.8.9
(c) Omission of self-closing devices
In the case of protected shafts which are interrupted by
barriers with fire resistance of at least half an hour at every
floor level or protected shafts containing sanitary pipes or
water pipes, fire resisting doors opening into the protected
shaft are not required to be installed with automatic
self-closing devices, provided such doors are kept closed
and locked at all times.
93
Diagram 3.8.9(c)
Provision of self-closing device for the inspection door of a protected
shaft, which is interrupted by barriers having ½-hour fire resistance at
every floor, is not required, if the door is kept closed and locked at all
times. The above relaxation is also applicable to TAS shafts, provided
they are interrupted by barriers with fire resistance of at least ½-hour at
every floor level.
An important point to note is the depth of the shaft which shall not
exceed 750mm. If it exceeds 750mm, the shaft would be considered as
a room and provision of self-closing device for the fire door becomes a
necessity.
The above relaxation is based on the understanding that it is unlikely
that a shaft would be converted to a store if its depth is less than
750mm and that the door would normally be kept in the locked
position when workmen are not carrying out servicing work. Also,
maintaining the door in the closed or locked position at all times is the
responsibility of the management corporation of the estate.
94
3.8.9
(d)
All protected shafts containing services shall not be
located within an exit staircase.
Diagram 3.8.9(d) - 1
A factory or warehouse building which does not require the provision of
smoke stop lobby to exit staircase by virtue of its height shall be required to
comply fully with the above requirement. All protected shafts containing
services are located in a common lobby adjoining the exit staircase.
Diagram 3.8.9(d) - 2
Although the services are enclosed in protected shafts, they are not permitted
to be located in exit staircase. The main reasons are :
a) Within the protected shaft, the combustible materials eg. Cables PVC
pipes are a source of fire risk. A fire could originate from these combustible
materials and spread in the exit staircase enclosure.
Exit staircase is a dedicated route for escape of occupants, services which
are not serving the staircase shall not be located inside the enclosure.
95
3.9
PROTECTION OF OPENINGS
3.9.1
Application
The provisions of this Clause are made in connection with the
protection of openings permitted in elements of structure or
other forms of fire resisting construction required to act as a
barrier to fire and smoke.
(No illustration)
For functional purposes, openings in compartment walls, floor etc are required
in buildings to allow movement of people and the installation of services such
as pipes, ventilation ducts etc. To prevent the spread of fire and smoke, such
openings shall be appropriately protected.
3.9.2
Fire doors
Fire doors for protection of openings shall comply with the
following:
(a)
Fire resisting doors shall have the appropriate fire resistance
as required by relevant parts of the Code, and two fire
resisting doors may be fitted in an opening if each door by
itself is capable of closing the opening and the two doors
together achieve the required level of fire resistance, and
Diagram 3.9.2(a) – 1
The two 1-hour fire door arrangement is deemed to satisfy compartmention
and equivalent to the fire resistance rating of the compartment wall (2 hours).
96
Diagram 3.9.2(a) - 2
The provision of fire doors shown in the above diagram usually occur in
separating walls, compartments or protecting structures.
(b)
All fire doors shall be fitted with an automatic self-closing
device which is capable of closing the door from any angle
and against any latch fitted to the door, and
(No illustration)
All fire doors are required to be fitted with an automatic self-closing
device, which shall not include rising butt. Self-closing device is not
required to be fitted to doors of protected shafts having a depth of not
more than 750mm under sub-clause 3.8.9(c).
Fire resisting door to exit openings of factory/warehouse units, protected
staircases, protected lobbies, exit passageway, compartment walls etc.
shall have minimum half-hour fire resistance. Doors to exit facilities shall
not be fitted with any locking device. However, doors to exit openings
of factory/warehouse units would be fitted with locking devices for
security reasons. As fire door is to protect the openings in exit facilities, it
should always remain in the closed position to prevent the spread of
smoke and heat. The main function of the self-closing device is to return
the door to its closed position after being opened for movement of
occupants, goods etc. The passage latch fitted to the door is to hold
the fire door in closed position to counteract the pressure differential
across the door opening in a fire situation.
Buildings may have card key access or automatic-locking devices fitted
to doors of exit staircases to prevent unauthorised access by outsiders.
97
To gain entry into the staircase or to exit from it into any floor, the
occupants need to key in a code number or use a card key access to
unlock or release the locking device to the door. In times of power
failure or activation of fire alarm system, the locking device would be
unlocked automatically and all the exit doors could be opened
manually. Prior approval should be obtained from SCDF “FSSD” before
any door to exit facilities is fitted with any form of locking device.
When the door to the exit facilities consists of double leaves or multiple
leaves, all the leaves shall be fitted with self-closing device and
sequential closer or also known as door selector.
Self-closing device to fire door shall be properly maintained regularly.
Faulty device shall be repaired immediately to prevent fire door being
left in the open position.
(c )
Where a self-closing device would be considered a
hindrance to the normal use of the building, fire resisting
doors may be held open as follows :
(i)
by a fusible link, or
(ii)
if the doors can be opened manually, by
electromagnetic or electro-mechanical devices which
can be activated by the presence of smoke and/or
the building alarm system,
(See illustration in Cl.1.2.20 under Definition in Volume I)
(d)
Any hinge on which a fire resisting door is hung shall be
made entirely of non-combustible materials having a
melting point of at least 8000 C , and
(No illustration)
3.9.2
(e)
Any fire door fitted in an opening which is provided as
a means of escape:
(i)
shall be capable of being opened manually,
without the use of key, tool, special knowledge or
effort for operation from the inside of the building;
and
(ii)
shall not be held open by any means other than
by an electromagnetic or electro- mechanical
device which can be activated by the presence
of smoke and/or the building alarm system,
provided that this shall not apply in the case of fire
98
doors opening into pressurised exit staircases.
(iii)
shall open in the direction of exit travel in
accordance with Cl. 2.3.9.
(See illustration in Cl.1.2.20 under Definition in Volume 1)
3.9.2
(f)
Fire doors where required to be provided shall be
constructed and installed to comply with specifications
stipulated under SS 332 Specification for Fire Doors.
Diagram 3.9.2(f)
All fire doors are required to bear PSB label and listed under the Product
Listing Scheme of Productivity and Standards Board. It is important to
note that fire door opening into pressurised exit staircases shall not be
fitted with electromagnetic or electro-mechanical device. This is to
ensure that the integrity of the pressurised exit staircase is maintained at
all times.
99
3.9.3
Pipes
(a) Pipes which pass through a separating wall, compartment wall
or compartment floor shall be kept as small as possible and
fire-stopped around the pipe. The nominal internal diameter of
the pipe shall be not more than the relevant dimension given in
Table 3.9A. Spacing between pipes shall be minimum 50mm or
½-diameter of the largest pipe, whichever is the larger.
Diagram 3.9.3 - 1
The clustering of pipes without proper spacing would further weaken the
integrity of the fire resisting walls in times of fire emergency.
100
Penetration of elements of structure by pipes
Diagram 3.9.3 - 2
UPVC pipes located in external corridor
Diagram 3.9.3 - 3
101
External corridor would be well ventilated. Hence lower fire risk is lower and the
threat of spread of fire and smoke from floor to floor is very much reduced.
(b)
(i)
Routing of gas pipes in basements
All gas pipes that are routed in basement shall be API pipes
with welded joints. These joints shall be 100% radiography
checked in accordance with sub-clause 3.4.2 (h) of SS CP
51. The gas pipes are not required to be fire rated if they
are running outside essential areas such as exit staircases,
smoke stop or fire fighting lobby, fire pump room, generator
room, fire command centre, etc. If they run into the
essential area, they are required to be encased in
masonry.
(ii) For mechanically ventilated basement, the gas pipes shall
be provided with pipe sleeves for the venting of gas pipes.
One end of the sleeve shall be exposed to the external as
specified in sub-clause 3.4.2 (g) of SS CP 51.
(iii) For naturally ventilated basement that complies with subclause 6.4.1(d)(iii)(b), the provision of pipe sleeve is not
required
(No illustration)
3.9.4
Ventilation ducts
Ventilation duct which passes directly through a compartment
wall or compartment floor shall comply with the following (a)
Where the ventilation duct does not form a protected
shaft or is not contained within a protecting structure,
(i)
the duct shall be fitted with a fire damper where it
passes through the compartment wall or
compartment floor, and
(ii)
the opening for the duct shall be kept as small as
practicable and any gap around the fire damper
shall be fire-stopped.
102
Diagram 3.9.4(a)
Proper fire stopping around the duct where it penetrates the
compartment floor/wall and provision of fire damper at the compartment
wall/floor would help to prevent fire and smoke spread from compartment
to compartment.
(b)
Where the ventilation duct forms a protected shaft or is
contained within a protecting structure, the duct shall be (i)
fitted with fire dampers at the inlets to the shaft and
outlets from it, and
(ii)
constructed and lined with materials in accordance
with the requirements in Chapter 7.
Diagram 3.9.4(b)
103
The provision of fire damper at the entry to the protected shaft would help
to complete the compartmentation to prevent fire or smoke from being
drawn into the protected shaft via ventilation duct.
(c)
`3.9.5
The installation of ventilation ducts and fire dampers shall
comply with the requirements in Chapter 7.
Flues
Duct encasing one or more flue pipes which passes through a
compartment wall or compartment floor shall be of non-combustible
construction having fire resistance of not less than half the minimum
period of fire resistance required for the compartment wall or
compartment floor through which it passes, except for kitchen flue
pipes when the fire resistance shall be as required for the
compartment wall or compartment floor.
Drawing 3.9.5 - 1
Separate kitchen exhaust shaft enclosed in masonry or dry wall construction shall
be provided for Kitchen (1) and (2). This is to prevent fire and smoke from
spreading from one compartment to another. The wall enclosing the shaft shall
have the same fire resistance as the compartment wall or floor.
3.9.6
Service pipings and ductings
Air ducts, sanitary pipings, gas pipes and other services that are likely to
permit the passage of flame or smoke in the event of a fire shall not be
permitted to pass through rooms housing fire pump, emergency
generator or fans handling smoke control system except where such
services are required for the operation of these equipment.
(No illustration)
104
3.10
3.10.1
EXIT STAIRCASES
Non- combustibility of structure
Every exit staircase, including the treads/risers and landing, shall be
constructed of non-combustible materials.
(No illustration)
3.10.2
Structure separating exit staircase
The exit staircase shall be separated from other parts of the building
by a masonry structure or drywall complying with Cl.3.8.7(c) which
shall have fire resistance for not less than the period required by
Cl.3.3 for Elements of Structure.
3.10.3 Exit Doors
Doors opening into the exit staircase shall have fire resistance of at
least half an hour and fitted with automatic self-closing device.
3.10.4 Finishes
Finishes to the ceiling/walls and floors of exit staircase shall be of
non-combustible materials.
Internal exit staircase
Diagram 3.10.4
105
The protecting structure, excluding the external wall, to the staircase shall be
constructed of masonry. Ceiling/wall and floor finishes shall be of noncombustible materials to ensure that the level of safety in the staircase is
maintained at all times. The only exception allowed is the handrail material.
3.11
CONCEALED SPACES
3.11.1
General Provision
Concealed spaces in a building shall be interrupted by
construction of cavity barrier to restrict the spread of smoke and
flames.
Diagram 3.11.1 - 1
Diagram 3.11.1 – 2
106
Concealed spaces or cavities in building provide a ready route or flue for
smoke and flame to spread undetected for quite some time, thus increasing
the risk to life safety of occupants in the building. This is particularly so in the
case of void spaces above a suspended ceiling or in a roof space or in a
raised floor system. Provisions are available in the Fire Code to reduce the risk
of concealed smoke and flame spread by the introduction of cavity barrier
when the area or linear dimensions of cavities exceed the limits as per Table
3.11A. Cavity barriers shall be constructed of non-combustible materials and
shall have at least half hour fire resistance.
3.11.2
Closing the edges of cavities
Cavity barriers shall be used to close the edges of cavities,
edges around openings through a wall, floor and any other part
of the construction which contains a cavity and to separate any
cavity in a wall, floor or any other part of the construction from
any other such cavity.
Diagram 3.11.2
“Cavity barrier” means any construction provided to close a cavity against,
or restrict the spread of smoke and flame within it.
In figure (I) above, cavity barriers are used to close the edges around the
window opening. Similar application is provided to window in external cavity
wall in figure (ii).
107
3.11.3
Interrupting cavities
Cavities including roof spaces shall be interrupted by cavity
barriers where a wall, floor, ceiling, roof or other part of the
construction abut the cavity, if there is provision for the element
of structure to form a fire resisting barrier. Such cavity barriers
shall be of fire resisting construction at least equal to the
provision for that required for the fire resisting barrier.
Figure (i)
Diagram 3.11.3 – (i)
Cavities must be closed where the fire barrier elements (compartment
walls) abut the cavity (including the frame of a door).
108
Figure (ii)
Diagram 3.11.3 – (ii)
Figure (iii)
Diagram 3.11.3 - (iii)
Any cavity within an element, or at the junction of two elements, must be
closed by a cavity barrier
109
Figure (iv)
Diagram 3.11.3-(vi)
It is a common practice to bring the compartment wall right-up to the
underside of the structural slab above. The cavity barrier above the
compartment wall shall be treated as an extension of the compartment
wall below.
Figure (v)
Diagram 3.11.3 – (v)
The roof space over a protected staircase must be separated by either a
cavity barrier at (a) having the same fire rating as the wall of the staircase
below, or a fire rated ceiling at (b). See Cl.1.2.8 under Definitions, Vol. 1 for
further illustration. Extending the masonry wall right up to the underside of
110
the roof coverings at (a) would meet the requirement under Cl.3.10 of
having masonry enclosure to exit staircase.
3.11.4
Sub-division of extensive cavities
Cavities, including roof spaces, unless otherwise permitted,
shall be sub-divided so that the maximum distance between
cavity barriers shall not exceed the relevant dimensions given
under Table 3.11A.
TABLE 3.11A
MAXIMUM DIMENSIONS OF CAVITIES
Location
of cavity
Purpose Group of
building or
compartment
*Class of surface
exposed in cavity
Max.
dimension in
any direction
Between roof
I & II
any
no limit
and ceiling
others
any
20m
Any other
any
Class 0
20m
cavity
any
any
8m
* excluding surface of any pipe, cable, conduit or insulation of any
pipe.
The main reason of limiting the dimension of cavities is to prevent fire or smoke
from spreading widely in large concealed space.
3.11.5
Fire resistance and fixing of cavity barriers
Cavity barriers shall be
(a)
Constructed to provide at least half an hour fire resistance, and
(b)
Tightly fitted to rigid construction or the junctions shall be fire
stopped to comply with the requirements of Cl. 3.12.
111
Diagram 3.11.5 - 1
Cavity barriers must be tightly fitted to rigid construction and mechanically
fixed in position wherever possible. Where this is not possible (for example, in
the case of a junction with slates tiles, corrugated sheeting or similar materials)
the junction should be fire-stopped to prevent the spread of fire and smoke in
the concealed space.
Cavity barriers must also be fixed so that performance will not be made
ineffective by:
(a)
Movement of the building due to subsidence, shrinkage or temperature
change; and
(b)
collapse in fire of any services penetrating them; and
(c)
failure in fire of fixings; and
(d)
failure in fire of any material or construction which they may abut. For
example, if a suspended ceiling is continued over the top of a fireresisting wall or partition, and direct connection is made between the
ceiling and the cavity barrier above the line of the wall or partition,
premature failure of the cavity barrier can occur when the ceiling
collapses. However, this does not arise if the ceiling is designed to
provide fire protection of 30 minutes or more.
112
Diagram 3.11.5 - 2
Compartment walls should be carried right up to the full storey height, to a
compartment floor above or to the roof coverings, as appropriate, The walls in the
ceiling above the common corridor shall not be treated as cavity barriers. They shall
be treated as extension of the compartment walls below.
The main purposes of extending the compartment walls into the ceiling space are
to complete the compartmentation to each apartment unit and to prevent smoke
and fire spread via the concealed ceiling space.
3.11.6
Openings in cavity barriers
A cavity barrier shall have no opening in it except for:
(a)
A door which has at least half an hour fire resistance and shall be
kept closed all time,
(b)
A pipe which complies with the provision under Cl. 3.9.3,
(c)
A cable or conduit containing one or more cables,
(d)
An opening fitted with suitably mounted automatic fire damper,
and
(e)
A duct which is fitted with a suitably mounted fire damper where it
passes through the cavity barrier.
113
Diagram 3.11.6
Penetrations of cavity barriers shall be restricted to those illustrated above. All openings
through cavity barriers must be no larger than necessary and be fire stopped. The fire
stopping shall not restrict thermal movement.
3.11.8
Raised floors with or without accessible panels
The construction of raised floors with or without accessible panels shall
comply with the following requirements :
(a)
The supporting structure shall be constructed of non-combustible
materials having a melting point of at least 800°C, and
(b)
The concealed space between the structural floors and raised floor
shall not be used for storage purpose, and
(c)
No services or installation shall be permitted within the concealed
space other than
114
(i)
electrical wiring in metal conduit and metal trunking in
compliance with the requirements of SS CP 5 Code of Practice
for Wiring of Electrical Equipment of Buildings;
(ii)
communication cables for computer equipment
(iii) fire protection installations serving the area, and
(d)
Where the raised floor is used as a plenum, requirements in
Cl.7.1.1(f) shall be satisfied, and
(See clause 7.1.1(f) for illustration)
(e)
Decking of the raised floor shall be constructed of non-combustible
material or where combustible material is used as core material, if
allowed in the case of sprinkler protected buildings, the top,
bottom, all sides and cut edges shall be covered with material with
surface property complying with Class 0 (excluding materials for
floor finishes), and
Diagram 3.11.8 (e)-1
Non-combustible raised floor panels and supports are allowed to be used in nonsprinkler or sprinkler protected buildings.
115
Diagram 3.11.8(e)-2
Raised floor panel constructed of combustible core, eg. chipboard, shall only be
allowed to be used in buildings protected by sprinkler system
(f)
In the case of raised floors with accessible panels, access sections
or panels shall be provided such that all concealed spaces
between the structural floor and raised floor are easily accessible,
and
(g)
Openings in the raised floor for entry of electrical cables shall be
effectively closed to prevent entry of debris or other combustible
material into the concealed spaces, and
(h)
All sides shall be properly sealed, and
(i)
The concealed space shall be sub-divided by cavity barriers such
that the maximum unobstructed area within the concealed space
does not exceed 930m², and
(j)
Where the concealed space is fitted with an automatic sprinkler
system which complies with the requirements in Chapter 6, cavity
barriers are not required, and
(k)
The height of concealed space measured between the top of the
structural floor and underside of the raised floor decking shall not
exceed 400mm and shall be fitted with automatic smoke detection
system complying with requirements of SS CP 10 Code of Practice
for the Installation and Servicing of Electrical fire Alarm Systems; and
in the case of sprinkler protected building, the height of concealed
space may exceed 400mm if the space is fitted throughout with an
automatic sprinkler system which complies with the requirements in
Chapter 6.
116
Diagram 3.11.8 (k)
The provision of cavity barriers shall comply with Table 3.11A of the Fire Code.
Non-sprinkler protected building
Cavity barriers shall be provided in accordance with Table 3.11A. The height of
concealed space (H), measured between the finished floor level and the underside
of the raised floor decking shall not exceed 400mm. The concealed space shall be
fitted with smoke detection system in accordance with SS CP 10 Code of Practice for
the Installation and Servicing of Electrical fire Alarm Systems. SS CP 10 also allows that
smoke detector system is not required to be provided in concealed space which
does not exceed 150mm in height – cl.2.1.3.1(b). Sprinkler system is applicable if the
height of concealed space exceed 400mm.
Sprinkler protected building
Cavity barriers shall be provided in accordance with Table 3.11A. Where the height
of the concealed space does not exceed 400mm, smoke detection system
complying with SS CP 10 shall be provided. The height of concealed space may
exceed 400mm if the space is fitted throughout with sprinkler system. Where sprinkler
system is provided inside the concealed space, cavity barriers are not required to be
provided – subclause (j).
3.11.8
(l)
Where the height of concealed space measured between
the top of the structural floor and the underside of the raised
floor decking is less than 50mm, the requirements on provision
of cavity barriers shall not be applicable.
(No illustration)
117
3.11.9
Provision for concealed spaces between floor or roof and suspended
ceilings
The Relevant Authority may consent to exempt from provision of cavity
barriers within the concealed spaces of suspended ceiling, provided
the following requirements are complied with :(a)
The concealed space shall not be used for storage purpose, and
(b)
The supporting elements shall be constructed of non-combustible
material, and
(c)
The exposed surfaces within the concealed space is of class 0
flame spread, (excluding surfaces of any pipe, cable, conduit or
insulation of any pipe) and
(d)
In the case of a detector protected building, if the concealed
space does not exceed 800mm in depth or if the concealed space
is fitted with detectors which comply with the requirements of
Chapter 6.
(e)
In the case of a sprinkler protected building:
(i)
if the concealed space does not exceed 400mm in depth, or
(ii)
if the concealed space exceeds 400mm and does not
exceed 800mm in depth and no combustible material is used
within the concealed space, (where the combustible content
is small in quantity, the Relevant Authority, may at its discretion,
rule that such combustible content may be irrelevant in
relation to this sub-clause), or
(iii) If the concealed space is fitted with an automatic sprinkler
system which complies with the requirements of Chapter 6.
(f)
In the case of other buildings, if the concealed space does not
exceed 800mm in depth.
118
Diagram 3.11.9(d)
Provision of cavity barriers in concealed ceiling space is not required if the following
requirements are complied with :
a) the space is not used for storage purpose; and
b) the supporting elements eg. ceiling hangers or supports are constructed of noncombustible material; and
c) the exposed surfaces within the concealed space is of Class 0 flame spread
(excluding surfaces of any pipe, cable, conduit or insulation of any pipe or duct);
and
d) concealed space does not exceed 800mm in depth; if exceeds 800mm, it shall be
fitted with smoke or heat detectors.
Diagram 3.11.9(e)(i)
Provision of cavity barriers in the concealed ceiling space is not required if the following
are complied with :
119
a) the space is not used for storage purpose; and
b) the supporting elements eg. ceiling hangers or supports are constructed of noncombustible material; and
c) the exposed surfaces within the concealed space is of Class 0 flame spread
(excluding surfaces of any pipe, cable, conduit or insulation of any pipe or duct); and
d) concealed space does not exceed 400mm in depth.
Sprinkler protected building - Depth of ceiling space exceeds 400mm but not
exceeding 800mm
Diagram 3.11.9(e)(ii)
Provision of cavity barriers in the concealed ceiling space is not required if the following
are complied with :
a) the space is not used for storage purpose; and
b) the supporting elements eg. ceiling hangers or supports are constructed of noncombustible material; and
c) the exposed surfaces within the concealed space is of Class 0 flame
spread(excluding surfaces of any pipe, cable, conduit or insulation of any pipe or
duct);
and
d) no combustible is used within the concealed space. However, where the
combustible content is small in quantity, the SCDF “FSSD” may, at its discretion
grants exemption, provided the space is protected by sprinklers installed on the
extended basis under sub-clause 6.6.1.2 of SS CP 52.
120
Concealed space is sprinklered protected – in accordance with Chapter 6
Diagram 3.11.9(e)(iii)
Provision of cavity barriers in the concealed ceiling is not required. See also cl.3.11.10
for further relaxation.
Other building – which neither requires detector nor sprinkler system
Diagram 3.11.9(f)
Provision of cavity barriers in the concealed ceiling space is not required if the
following are complied with :
a) the space is not used for storage purpose; and
b) the supporting elements eg. ceiling hangers or supports are constructed of noncombustible material; and
c) the exposed surfaces within the concealed space is of Class 0 flame spread
(excluding surfaces of any pipe, cable, conduit or insulation of any pipe or
duct); and
121
3.11.10
Exemption of cavity barriers in ceiling space
Where the concealed space of suspended ceiling is fitted with an
automatic sprinkler system which complies with the requirements in
Chapter 6,
(a)
The concealed space may be exempted from provision of cavity
barriers, and
(b)
Combustible materials and materials with other than Class 0 flame
spread may be used for the supporting elements and exposed
surfaces of materials within the concealed space, provided the
ceiling is not situated over an exit passageway, smoke-stop lobby
or other designated means of escape facilities.
(No illustration)
i)
ii)
3.11.11
Where the concealed ceiling space is protected by automatic sprinkler system,
the above clause allows the following :
a)
Provision of cavity barrier is exempted;
b)
Combustible materials such as hardwood timber hangers for ceiling; and
c)
Exposed surfaces within the ceiling space may be of any class other than
Class 0 flame spread ie. timber members.
The above relaxation shall not apply if the above ceiling construction is situated
over an exit passageway, smoke-stop lobby or other designated means of
escape facilities.
Suspended ceiling over protected areas
The concealed spaces of suspended ceiling over an exit passageway,
smoke-stop lobby, exit staircase or other designated means of escape
facilities, shall comply with the following:
(a)
the ceiling supporting elements and the ceiling shall be
constructed of non-combustible materials; and
(b)
the exposed surfaces within the concealed space shall be of Class
0 surface flame spread.
122
Diagram 3.11.11
The main concern is that spaces meant for safe escape of occupants shall be kept
free of combustible materials. Common corridors are treated as escape routes. The
exposed surfaces within ceiling space shall have a flame spread rating of Class ‘0’.
3.11.11
(c) Where sprinkler system is installed within the concealed spaces
at smoke stop lobby/fire fighting lobby, the ceiling supporting
elements and its exposed surface may have a surface spread
of flame not lower than class 2.
(No illustration)
3.12.1
General provision
Openings for pipes, ducts, conduits or cables which pass through
any part of an Element of Structure (except for a part which does
not serve as a fire resisting barrier) or Cavity Barrier shall be :
(a)
Kept as few in number as possible, and
(b)
Kept as small as practicable, and
(c)
All gaps shall be filled with fire-stopping material.
123
Diagram 3.12.1
Fire stopping is concerned with ensuring that the fire-resisting capability
of a component ,i.e separating wall, compartment wall/floor, cavity
barrier is not diminished or impaired when penetrated by services for
example, a pipe, ducts etc.
Therefore whenever gaps are created by the penetration of such pipes,
ducts in the fire rated wall/floor, they must be kept as few as possible.
The spacing and internal diameter of pipes passing through any
elements of structure or cavity barrier shall comply with Cl.3.9.3 and
Table 3.9A
3.1.2
3.12.2
FIRE STOPPING
Fire stopping
Fire stopping shall be of material having the necessary fire
resistance when subjected to test under BS 476 Pt 20 or other
acceptable standards.
(No illustration)
3.12.3
Materials for fire-stopping
Suitable fire stopping materials include:
(a)
Proprietary fire stopping and sealing systems (including
those designed for service penetrations) which have been
shown by test to maintain the fire resistance of the wall or
124
other element, subject to approval by the Relevant
Authority.
(b)
Other fire-stopping materials include:
(i)
cement mortar;
(ii)
gypsum based plaster;
(iii)
cement or gypsum based vermiculite/perlite mixes;
(iv)
glass fibre, crushed rock, blast furnace slag or
ceramic based products (with or without resin
binders), and
(v)
intumescent mastics.
The method of fire stopping and choice of materials should
be appropriate to the situation and its application.
(No illustration)
To prevent displacement, materials used for fire-stopping should be
reinforced with (or supported by) materials of limited combustibility in
the following circumstances:
(i)
in all cases where the unsupported span is greater than 100mm,
and
(ii)
in any other cases where non-rigid materials are used (unless
they have been shown to be satisfactory by test).
Preference should be given to proprietary fire-stopping and sealing
system.
When cement mortar or gypsum board plaster or cement or gypsum
based vermiculite/perlite mixes is used as fire stopping material, care
should be exercised to ensure that workmen properly fill up the entire
gaps with the appropriate fire stopping material instead of carrying
cosmetic application by just filling up the gaps superficially.
125
3.13
RESTRICTION OF SPREAD OF FLAME OVER SURFACES OF WALLS
AND CEILING
3.13.1
Requirements for Class 0
Any reference to a surface being Class 0 shall be construed as a
requirement that (a)
The material of which the wall or ceiling is constructed shall
be non-combustible throughout; or
(b)
The surface material (or, if it is bonded throughout to a
substrate, the surface material in conjunction with the
substrate) shall have a surface of Class 1 and if tested in
accordance with BS 476: Part 6 shall have an index of
performance (I) not exceeding 12 and a sub-index (I) not
exceeding 6.
(No illustration)
BS 476:Part 6 refers to a standard fire test for propagation of products.
Under this test, there is a means of comparing the contribution of
combustible building materials to the growth of a fire by providing a
measure of the rate of heat evolution of the samples, exposed in a
small combustion chamber.
The performance of each sample is expressed as a numerical index
from 0 to 100 or more. Low values of the indexes indicate a low rate of
heat release. Three to five specimens are tested.
Index of performance I = i1 + i2 + i3 where sub-index i1 is derived
from the first three minutes of test, i2 from the following seven minutes,
and i3 from the final ten minutes. A high index i1 indicates an initial
rapid ignition and heat release.
3.13.2
Requirements for a class other than Class 0 classification
Any reference to a surface being of a class other that Class 0
shall be construed as a requirement that the material which the
wall or ceiling is constructed shall comply with the relevant test
criteria as to surface spread of flame specified in relation to that
class in BS 476: Part 7.
(No illustration)
126
Test under BS 476: Part 7 refers to a standard fire test for the classification of
the surface spread of flame of products.
This test is able to determine the tendency of surfaces of flat materials to
support the spread of flame across their surfaces and specifies a method of
classification appropriate to wall and ceiling linings. Class 1 represents the
best performance, followed in descending order by Class 2, Class 3 and Class
4.
3.13.3
Class 0 shall be regarded as the highest class followed in
descending order by Class 1, Class 2, Class 3 and Class 4, as set
here under:
*
Class 0 - Surface of no Flame Spread. Those surfaces that
conform to the requirements of Cl. 3.13.1.
*
Class 1 - Surface of Very Low Flame Spread. Those surfaces
on which not more than 150mm mean spread of flames
occurs under the relevant test conditions.
*
Class 2 - Surface of Low Flame Spread. Those surfaces on
which during the first 1½ minutes of test, the mean spread of
flame is not more than 375 mm and the final spread does not
exceed 450 mm under the relevant test conditions.
*
Class 3 - Surface of Medium Flame Spread. Those surfaces
on which during the first 1½ minutes of test, the mean
spread of flame is not more than 375 mm and during the
first 10 minutes of test is not more than 825 mm under the
relevant test conditions.
*
Class 4 - Surface of Rapid Flame Spread. Those surfaces on
which during the first 1-1/2 minutes of test the mean spread
of flame is more than 375 mm and during the first 10 minutes
of test is more than 825 mm under the relevant conditions.
(No illustration)
The reason for having Class 0 is that Class 1 covered too wide a range of
performance for use in critical areas. Where a higher degree of
protection is required, for example in smoke stop lobbies, exit staircases,
exit passageways (which constitute the escape route), Class 0 is
specified.
127
3.13.4 Class of flame spread to be not lower than specified
The surface of a wall or ceiling in a room/space shall be of a
class not lower than specified as relevant in the Table 3.13A,
provided that (a)
Where an automatic sprinkler system is fitted throughout
in the building in compliance with the requirements in
Chapter 6, there is no control on the surface of flame
rating in room / space, except for the following
occupancies / usage:
(iii)
(b)
Exit staircase, exit passageway and smoke-stop /
fire fighting lobbies.
Where a building is not protected by automatic sprinkler
system, surfaces of the walls and ceilings may be of a
surface class not lower than class 3 to the extent
permitted by Cl 3.13.5 (a) and Cl 3.13.5 (b) respectively.
Diagram 3.13.4
Wall and ceiling finishes to exit staircase (including exit passageway) shall be
of non-combustible materials or Class 0 ( if sprinkler protected). For rooms, the
extent of wall and ceiling finishes ( no control if sprinkler protected or class 1 if
not sprinkler protected ) shall comply to Cl.3.13.5 (a) and (b) respectively for
area that can not be lower than class 3.
128
3.13.5 (a)
Where class of flame spread may be of any class not
lower than class 3
Any part of the surface of a wall in a room or
compartment may be of any class not lower than Class
3 if the area of that part ( or if there are two or more
such parts, the total area of those parts) does not
exceed the following (ii)
in any other case, 60 m2.
Fig.(1)
Diagram 3.13.5(a)(ii) - 1
Computation of 60m² will be based on total surface areas having not lower
than Class 3 of walls 1 + 2 + 3 + 4.
Fig. (i)
129
Fig. (II)
Fig. (III)
Diagram 3.13.5(a)(ii) – 2
In situation where multiple floors are interconnected to form one
compartment by atrium design, waiver application is required to vary the
max. 60sq.m
For Class 3 wall finishes, the total area of 60sq.m excludes :
(i)
door frames and unglazed parts of doors;
(ii)
window frames and frames in which glazing is fitted;
(iii)
architraves cover moulds, picture rails, skirtings and similar narrow
members; and
(iv)
fitted furniture.
130
(b)
Any part of the surface of a ceiling may be of any class
not lower than Class 3 if that part of the surface is the
face of a layer of material the other face of which is
exposed to the external air (skylight included) and (i)
*
the ceiling is that of a circulation space
excluding smoke-stop lobby, exit staircase and
exit passageway in a building or compartment
of any purpose group, and
*
the area of that part does not exceed 2.5 m²,
and
the distance between that part and any other
such part is not less than 3.5 m, or
*
Diagram 3.13.5(b)(i)
Any part of a ceiling to circulation space eg. corridor may have not lower than
class 3 flame spread, provided each part shall not exceed 2.5 sq.m and is
separated from other such part by minimum 3.5m.
(ii) * the ceiling is that of a room in a building or
compartment of purpose group VI, and
* the area of that part does not exceed 5.0m², and
* the distance between that part and any other such part
is not less than 1.8m, and
131
Diagram 3.13.5(b)(ii)
•
Factories and warehouses are usually provided with translucent roof
sheets or sky light for natural lighting.
•
Any part of ceiling which is combustible shall have an area not
exceeding 5m² and a class not lower than Class 3 flame spread. It
shall be separated from any such part by at least 1.8m
•
The aggregate area of such part of ceiling shall not exceed 20% of
the floor area of the room or compartment.
(iii)
that part and all other such parts are evenly
distributed over the whole area of the ceiling and
together have an area which does not exceed 20%
of the floor area of the room, or
Unenclosed loading/unloading platform
Diagram 3.13.5(b)(iii) – 1
132
Covered linkway connecting 2 buildings
Diagram 3.13.5(b)(iii) - 2
In-addition to the above, ceilings to balcony, verandah, open carport are
also allowed to have not lower than Class 3 flame spread. The above
relaxation is allowed as the ceilings are located at the periphery of the
building where smoke and heat could easily be dispersed into the exterior
air.
(iv)
the ceiling is that of a balcony, verandah, open
carport, covered way or loading bay which
(irrespective of its floor area) has at least one of its
longer sides wholly and permanently open, or
Diagram 3.13.5(b)(iv) - 1
133
Diagram 3.13.5(b)(iv) - 2
Diagram 3.13.5(b)(iv) - 3
A garage or outbuilding may have ceiling not lower than Class 3 flame spread,
provided the gross floor area does not exceed 40m²
(v) the ceiling is that of a garage or outbuilding which (
irrespective of whether it forms part of a building or is a
building which is attached to another building or wholly
detached ) has floor area not exceeding 40 m2.
134
3.13.6
Exception
Wall and ceiling finishes in the form of thin sheet of not more than
1.0 mm thickness mounted on a non-combustible substrate will not
be subject to the requirement of surface spread of flame provisions
provided that this exception shall not apply to smoke-stop / fire
fighting lobbies, exit staircases and passageways.
(No illustration)
The above clause grants relaxation on the control of wall and ceiling finishes
which are not more than 1.0 mm thick mounted on non-combustible substrate,
provided these finishes are not used in smoke-stop lobbies, exit staircases and
exit passageways. The main concern is that all protected routes meant for
escape of occupants shall be kept free of combustible finishes.
3.14
ROOFS
3.14.1
Roof construction
Surface of materials for roof covering and roof construction shall
have a surface spread of flame rating not lower than class 1,
except in the case of buildings that are protected throughout with
automatic sprinkler system in compliance with Chapter 6.
(No illustration)
3.14.3
Roof junction with separating wall and compartment wall
At the junctions with separating wall or compartment wall, roof
construction shall comply with the relevant requirements under
Cl.3.6.3 and Cl.3.7.4 respectively.
(See illustration and comments under Cl.3.6.3)
3.14.4
Roof terrace
Roof terrace shall not be roofed over. If it is either partially or fully
roofed over, it shall be considered as a habitable floor.
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Diagram 3.14.4
Roof Terrace
a) Means of escape
Roof terrace even if not roofed over could be used by building owners to hold
private functions. In this respect, the roof terrace would attract additional
occupant load, which could be sizeable, depending on the type of function
proposed, for example, a private dinner function could be held on the open
roof terrace. The guests and the hosts that are attending the private function
on the roof terrace would be subject to the risk of a fire that could break out in
any of the floor space below the roof terrace. For this reason, roof terrace,
whether roof over or not should be subjected to compliance with exit capacity
and travel distance requirements under the fire code. Roof terrace which
exceeds the floor area of 60sq. m shall be provided with a separate exit at
terrace level.
b) Habitable height
For the purpose of determining the habitable height of a building, roof terrace
that is either partially or fully roofed over shall be considered as a habitable
floor. Thus, if the roof terrace is the highest habitable floor, the habitable height
of a building shall be measured from the lowest level of the fire engine access
road to the finished floor level of the highest habitable floor.
In the above diagram, the habitable height of the building shall be measured
up to the finished floor level of the terrace. Otherwise it shall be measured up to
the finished floor level of the 3rd storey.
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3.15
3.15.1
MATERIALS FOR CONSTRUCTION
(a)
Materials used in the construction of building elements shall
comply with the provisions stated under this section in
addition to the performance requirements such as for fire
resistance and limit to spread of flame as stipulated in other
relevant sections of the code.
(c)
Flame retardant chemicals are permitted to be used for
upgrading of fire resistance rating or surface spread of
flame of timber or any combustible materials, subject to the
following:
(i)
The chemical treatment process is part and parcel of
the manufacturing process to produce the finished
product ;
(ii)
The chemical treatment is by means of pressure
impregnation conforming to SS CP: 1 – Use of Timber
in Building Construction , or the manufacturer’s
specification in accordance to the prototype test, for
timber and other combustible materials respectively.
(iii)
The treated materials/products have been subjected
to fire test as required under Cl 3.4.1 or Cl 3.13.1
(No illustration)
1. It is recognised as an alternative means to protecting
timber construction in buildings.
2. However, we have to understand the limitations on the use
of flame retardant chemicals for upgrading of fire
resistance and/or surface spread of flame rating of
combustible materials. The limitations are as follows:-
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a. The chemicals may deteriorate after exposing to the
environment for a long duration. After such, the fire
resistance performance or the surface spread of flame
rating may be adversely affected over time.
b. The inherent property of the flame-retardant chemical
to resist fire spread may be affected when cleaning
agent is constantly applied to the surface of the
combustible material.
c. There is no specific method and control of treatment of
the flame-retardant chemical. This would lead to poor
performance as a result of shoddy construction of the
materials.
d. There is no certainty on the duration for which the fire
property in a material applied with such a chemical
can last.
3. For buildings which are not under Conservation, the use of
timber materials should be carefully considered and should
be avoided where possible.
4. Building owners and occupiers should be made aware of
the above mentioned limitations on the use of flame
retardant chemicals. In the course of using the premises,
building owners and occupiers shall not do anything to
cause the retardant treatment to timber members to
deteriorate.
3.15.2
All elements of structure shall be constructed of noncombustible materials in addition to the relevant provisions as
follows:
Cl.3.3 for fire resistance of elements of structure,
Cl.3.5.1, 3.5.2 & 3.5.4 for External Walls,
Cl.3.6.1(c)/(d) & 3.6.5 for Separating Walls,
Cl.3.7.1(c)/(d), 3.7.5 & 3.7.6 for Compartment Walls and
Compartment Floors,
Cl.3.8.2(c), 3.8.4, 3.8.7(c), 3.8.8(b), 3.8.8(e) and 3.8.9(a) for
Protected Shafts.
3.15.3
Materials used for the protection of openings shall comply with
the relevant provisions of cl.3.9 of the code for protection of
openings.
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3.15.4
Exit staircases shall be constructed of non-combustible materials to
comply with the provision of Cl.3.10.1.
(See Cl.3.10.1 to 3.10.4 for illustration and explanation)
3.15.5
Materials used for the construction of raised floors shall comply with the
provisions of cl.3.11.8(a) and cl.3.11.8(e).
3.15.6
Materials used for construction of ceiling and its supports shall comply
with Table 3.13B, except for supports that are required to comply with
cl.3.11.9 (b).
3.15.7
Construction of ceilings and ceiling supports located within sprinkler
protected building shall comply with the provision of cl.3.11.10(b).
3.15.8
Materials used for fire stopping shall comply with the relevant provisions
of cl.3.12.2 and 3.12.3.
3.15.9
Materials used on the surfaces of walls and ceilings are required to
meet the requirements for restriction of spread of flame and to comply
with the performance requirements as stipulated under cl.3.13.
3.15.10
Materials used for roof construction shall comply with the provisions of
cl.3.14.1.
3.15.11
Internal non-load bearing walls in buildings shall comply with Table
3.13B and the materials for surface finishes of internal non-load bearing
walls shall not be treated as part of the wall and shall comply with the
relevant provisions of cl 3.13.
(No illustration)
Materials for surface finishes of all the walls, non-load bearing, separating and
compartment walls shall comply with Cl.3.13.5 and Cl.3.13.6.
3.15.12
(a)
Composite panels which consist of plastic core shall not be
used either for the construction of internal non-load bearing
walls, ceilings, external walls or as cladding to external walls of
all buildings unless prior approval has been obtained from the
Relevant Authority.
(No illustration)
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Composite panels are used as external walls or cladding of external walls
to buildings. Prior approval should be obtained before any composite
panel is erected on site. The main concern is that composite panels when
subjected to fire would burn vigorously to produce thick, poisonous fumes.
(b)
Materials with surface flame spread rating of not lower than
Class 3 shall be permitted to be used for the construction of
partition for toilet cubicles. If the material used is of Class 3
surface flame spread rating, total exposed surface area of
the partitions within the toilet shall not be more than 60m2 .
Diagram 3.15.12 (b)
Materials with surface flame spread rating of not lower than Class 3,
including phenolic panels, are allowed to be used in the construction of
partitions for toilet cubicles only.
The exposed surface area of not more than 60m2 of the partitions within the
toilet refers to the surface exposed to air, inside and outside, of the
partitions.
The reasons for allowing materials with surface flame spread rating of not
lower than Class 3, including phenolic panels, in the construction of toilet
cubicles are:a. toilets are considered as wet areas;
b. the amount of combustible materials would be limited;
c. the toilets are subjected to low transient occupancy.
3.15.13 Fire rated glass wall/door to compartment walls, compartment floors,
smoke stop lobby and fire fighting lobby, and protected shafts not
containing exit staircase and fire lift.
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(a)
The walls and doors shall have the necessary fire resistance,
including insulation, when subject to test under BS 476: Part 2023; and
(b)
The walls and doors shall meet the class A of the Impact
Performance requirements when subject to test under BS 6206
or AS 2208.
3.15.14 Internal non-load bearing walls, ceilings and finishes shall not contain
any plastic material.
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